Articles de revues : « Kagome layers »

1

Xie, Sheng-Yi, Xian-Bin Li, Wei Quan Tian, Nian-Ke Chen, Yeliang Wang, Shengbai Zhang et Hong-Bo Sun. « A novel two-dimensional MgB6 crystal : metal-layer stabilized boron kagome lattice ». Physical Chemistry Chemical Physics 17, n^o 2 (2015) : 1093–98. http://dx.doi.org/10.1039/c4cp03728f.

Texte intégral

Résumé :

Based on first-principles calculations, we designed for the first time a boron-kagome-based two-dimensional MgB₆ crystal, in which two boron kagome layers sandwich a triangular magnesium layer.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Gautam, Rinoj, et Sridhar Idapalapati. « Compressive Properties of Additively Manufactured Functionally Graded Kagome Lattice Structure ». Metals 9, n^o 5 (3 mai 2019) : 517. http://dx.doi.org/10.3390/met9050517.

Texte intégral

Résumé :

Cellular lattice structures have important applications in aerospace, automobile and defense industries due to their high specific strength, modulus and energy absorption. Additive manufacturing provides the design freedom to fabricate complex cellular structures. This study investigates the compressive properties and deformation behavior of a Ti-6Al-4V unit Kagome structure fabricated by selective laser melting. Further, the mechanical performance of multi-unit and multi-layer Kagome structure of acrylonitrile butadiene styrene (ABS) ABS-M30™ manufactured by fused deposition modeling is explored. The effect of a number of layers of Kagome structure on the compressive properties is investigated. This paper also explores the mechanical properties of functionally graded and uniform density Kagome structure. The stiffness of the structure decreased with the increase in the number of layers whereas no change in peak load was observed. The functionally graded Kagome structure provided 35% more energy absorption than the uniform density structure.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Yang, Yuxin, Wenhui Fan, Qinghua Zhang, Zhaoxu Chen, Xu Chen, Tianping Ying, Xianxin Wu et al. « Discovery of Two Families of Vsb-Based Compounds with V-Kagome Lattice ». Chinese Physics Letters 38, n^o 12 (1 décembre 2021) : 127102. http://dx.doi.org/10.1088/0256-307x/38/12/127102.

Texte intégral

Résumé :

We report the structure and physical properties of two newly discovered compounds AV8Sb12 and AV6Sb6 (A = Cs, Rb), which have C 2 (space group: Cmmm) and C 3 (space group: R 3 ¯ m ) symmetry, respectively. The basic V-kagome unit appears in both compounds, but stacking differently. A V2Sb2 layer is sandwiched between two V3Sb5 layers in AV8Sb12, altering the V-kagome lattice and lowering the symmetry of kagome layer from hexagonal to orthorhombic. In AV6Sb6, the building block is a more complex slab made up of two half-V3Sb5 layers that are intercalated by Cs cations along the c-axis. Transport property measurements demonstrate that both compounds are nonmagnetic metals, with carrier concentrations at around 1021 cm−3. No superconductivity has been observed in CsV8Sb12 above 0.3 K under in situ pressure up to 46 GPa. Compared to CsV3Sb5, theoretical calculations and angle-resolved photoemission spectroscopy reveal a quasi-two-dimensional electronic structure in CsV8Sb12 with C 2 symmetry and no van Hove singularities near the Fermi level. Our findings will stimulate more research into V-based kagome quantum materials.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Lee, Jeong-Eun, Ulrich Burkhardt et Alexander Christoph Komarek. « Synthesis of a New Ruthenate Ba26Ru12O57 ». Crystals 10, n^o 5 (30 avril 2020) : 355. http://dx.doi.org/10.3390/cryst10050355.

Texte intégral

Résumé :

Single crystals of Ba 26 Ru 12 O 57 were grown by the floating zone method. The crystal structure is formed by an alternating stacking of pseudo-hexagonal Ru single layers and double layers. The Ru ions within the double layers are dimerized (Ru 2 O 9 ) whereas the Ru ions within the single layers arrange in a distorted Kagome lattice of trigonal bipyramidally coordinated RuO 5 polyhedra. Additionally, this Kagome lattice is “decorated” with RuO 6 octahedra that are situated in the central free spaces within this Kagome lattice. According to the composition, the oxidation state of most of the Ru ions should be formally close to 5+.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Wulff, L., et Hk Müller-Buschbaum. « Isolierte trigonale SrO6 – Prismen verknüpfen Kagome-Netze im Strontium-Manganat(IV)-Tellurat(VI) : SrMnTeO6 / Kagomé Layers Connected by Isolated Trigonal SrO6 Prisms in the Strontium Manganate(IV) Tellurate(VI) : SrMnTeO6 L ». Zeitschrift für Naturforschung B 53, n^o 3 (1 mars 1998) : 283–86. http://dx.doi.org/10.1515/znb-1998-0305.

Texte intégral

Résumé :

Abstract Single crystals of the hitherto unknown compound SrMnTeO6 have been prepared from Sr(OH)2 ·8H2O , MnCO3(aq) and TeO2 in air by crystallization below the melt range. X-ray investigations showed hexagonal symmetry, space group D33h -P6̅2m, lattice constants a = 5.143( 1), c = 5.384(2) A, Z = 1. SrMnTeO6 is characterized by staggered [(Mn/Te)6O18] Kagome layers along [001]. These layers are connected by Sr2+ ions, resulting in SrO6 prisms isolated from each other. The structure is discussed with respect to the connection of Kagome nets in the quaternary oxides of the Ba3Ln4O9 type.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Yin, Qiangwei, Zhijun Tu, Chunsheng Gong, Shangjie Tian et Hechang Lei. « Structures and physical properties of v-based kagome metals csv₆sb₆ and csv₈sb₁₂ * ». Chinese Physics Letters 38, n^o 12 (1 décembre 2021) : 127401. http://dx.doi.org/10.1088/0256-307x/38/12/127401.

Texte intégral

Résumé :

We report two new members of V-based kagome metals CsV6Sb6 and CsV8Sb12. The most striking structural feature of CsV6Sb6 is the V kagome bilayers. For CsV8Sb12, there is an intergrowth of two-dimensional V kagome layers and one-dimensional V chains, and the latter ones lead to the orthorhombic symmetry of this material. Further measurements indicate that these two materials exhibit metallic and Pauli paramagnetic behaviors. More importantly, different from CsV3Sb5, the charge density wave state and superconductivity do not emerge in CsV6Sb6 and CsV8Sb12 when temperature is above 2 K. Small magnetoresistance with saturation behavior and linear field dependence of Hall resistivity at high field and low temperature suggest that the carriers in both materials should be uncompensated with much different concentrations. The discovery of these two new V-based kagome metals sheds light on the exploration of correlated topological materials based on kagome lattice.

Styles APA, Harvard, Vancouver, ISO, etc.

7

Aidoudi, Farida H., Lewis J. Downie, Russell E. Morris, Mark A. de Vries et Philip Lightfoot. « A hybrid vanadium fluoride with structurally isolated S = 1 kagome layers ». Dalton Trans. 43, n^o 17 (2014) : 6304–7. http://dx.doi.org/10.1039/c4dt00452c.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

Yang, Ming, Su-Yun Zhang, Wen-Bin Guo, Ying-Ying Tang et Zhang-Zhen He. « Spin-frustration in a new spin-1/2 oxyfluoride system (Cu13(VO4)4(OH)10F4) constructed by alternatively distorted kagome-like and triangular lattices ». Dalton Transactions 44, n^o 35 (2015) : 15396–99. http://dx.doi.org/10.1039/c5dt02752g.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

9

Sun, Yu-Wei, Zhan-Wei Li et Zhao-Yan Sun. « Multiple 2D crystal structures in bilayered lamellae from the direct self-assembly of 3D systems of soft Janus particles ». Physical Chemistry Chemical Physics 24, n^o 13 (2022) : 7874–81. http://dx.doi.org/10.1039/d1cp05894k.

Texte intégral

Résumé :

Multiple highly-ordered 2D crystal structures, including a triangular lattice, kagome lattice, and even a Frank–Kasper σ phase, are found within the layers of bilayered lamellae self-assembled directly from 3D systems of soft Janus particles.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Mu, Chao, Qiangwei Yin, Zhijun Tu, Chunsheng Gong, Ping Zheng, Hechang Lei, Zheng Li et Jianlin Luo. « Tri-hexagonal charge order in kagome metal CsV₃Sb₅ revealed by ¹²¹Sb nuclear quadrupole resonance ». Chinese Physics B 31, n^o 1 (1 janvier 2022) : 017105. http://dx.doi.org/10.1088/1674-1056/ac422c.

Texte intégral

Résumé :

We report 121Sb nuclear quadrupole resonance (NQR) measurements on kagome superconductor CsV3Sb5 with T c = 2.5 K. 121Sb NQR spectra split after a charge density wave (CDW) transition at 94 K, which demonstrates a commensurate CDW state. The coexistence of the high temperature phase and the CDW phase between 91 K and 94 K manifests that it is a first order phase transition. The CDW order exhibits tri-hexagonal deformation with a lateral shift between the adjacent kagome layers, which is consistent with 2 × 2 × 2 superlattice modulation. The superconducting state coexists with CDW order and shows a conventional s-wave behavior in the bulk state.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Zhang, Dongyao, Zhipeng Hou et Wenbo Mi. « Anomalous and topological Hall effects of ferromagnetic Fe₃Sn₂ epitaxial films with kagome lattice ». Applied Physics Letters 120, n^o 23 (6 juin 2022) : 232401. http://dx.doi.org/10.1063/5.0096144.

Texte intégral

Résumé :

Fe3Sn2, a ferromagnetic alloy with a kagome lattice, has attracted much attention from research communities owing to its special crystal structure and symmetry, which gives rise to numerous intriguing magneto-electronic properties, including the topological Hall effect, skyrmionic bubbles, Dirac cones, and Weyl points. To study such physical properties, Fe3Sn2 epitaxial films without buffer layers are in urgent need. In this work, we fabricated the Fe3Sn2 epitaxial films without buffer layers using the facing-target magnetron sputtering method, and their magneto-electronic transport properties were investigated systematically. It is found that the sign of the Hall resistivity slope in a high-field region is reversed when the temperature decreases below 100 K, suggesting a temperature-induced transition of charge carriers from electrons to holes. Moreover, a non-negligible topological Hall resistivity subtracted from the anomalous Hall resistivity is depicted, and its value is comparable to that of the Fe3Sn2 single crystals. These results not only offer a clear understanding of ferromagnetic Fe3Sn2 films with the kagome lattice but also provide guidance for fabrication and application of epitaxial Fe3Sn2 films.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Yasin, Sohail, Zamir Ahmed, Zhu Chenyang et Yao Juming. « Altering Sound Absorption in Acoustic Fabrics via Different Honeycomb Cell Patterns ». Research Journal of Textile and Apparel 18, n^o 3 (1 août 2014) : 22–27. http://dx.doi.org/10.1108/rjta-18-03-2014-b003.

Texte intégral

Résumé :

This study shows the result of experiments carried out with different weave patterns introduced in honeycombed acoustic fabrics by varying the cell patterns. The designed honeycomb fabrics with regular triangular, hexagonal and kagome lattice woven patterns are introduced into acoustic fabrics. Acoustic fabrics have sandwiched and porous layers for absorbing different sound waves that convert sound energy into thermal energy, thus allowing a minimal number of waves to penetrate. The sound absorption of the prepared samples is tested twice by using the microphone transfer function method according to international standard ISO 10534-2. The results show that regular hexagonal weave patterns have higher noise reduction coefficient (NRC) values at high frequency sound waves. At low frequencies, the kagome lattice weave pattern in fibreglass has high NRC values.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Hong, Deshun, Changjiang Liu, Jianguo Wen, Qianheng Du, Brandon Fisher, J. S. Jiang, John E. Pearson et Anand Bhattacharya. « Synthesis of antiferromagnetic Weyl semimetal Mn₃Ge on insulating substrates by electron beam assisted molecular beam epitaxy ». APL Materials 10, n^o 10 (1 octobre 2022) : 101113. http://dx.doi.org/10.1063/5.0116981.

Texte intégral

Résumé :

The antiferromagnetic kagome semimetals Mn3X (X = Ge, Sn, Ga) are of great interest due to properties arising from their Berry curvature, such as large anomalous Nernst and anomalous Hall coefficients, and spin to charge conversion efficiencies at ambient temperatures. However, the synthesis of epitaxial thin films of Mn3Ge in the desired hexagonal phase has been challenging because they do not wet insulating substrates, necessitating the use of a metallic buffer layer. Furthermore, a ferrimagnetic tetragonal phase also forms readily under typical growth conditions, interfering with hexagonal phase properties. We have synthesized atomically smooth and continuous epitaxial thin films of hexagonal Mn3Ge directly on insulating LaAlO3 (111) substrates using electron beam assisted molecular beam epitaxy, using a three-step process that mitigates the formation of the tetragonal phase. The anomalous Nernst coefficient is found to be more than six times larger in our films than in sputtered thin films of Mn3Ge and significantly larger than that of Fe. Our approach can be used to grow thin layers of kagome materials, without interference from a buffer layer in transport properties, and may be applicable to a broader range of materials with large surface energies that do not grow readily on insulating substrates.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Kaboudvand, Farnaz, Samuel M. L. Teicher, Stephen D. Wilson, Ram Seshadri et Michelle D. Johannes. « Fermi surface nesting and the Lindhard response function in the kagome superconductor CsV₃Sb₅ ». Applied Physics Letters 120, n^o 11 (14 mars 2022) : 111901. http://dx.doi.org/10.1063/5.0081081.

Texte intégral

Résumé :

The recently discovered kagome net compounds AV3Sb5 ( A = K, Rb, and Cs) become superconducting on cooling, in addition to displaying interesting topological features in the electronic structure. They also exhibit charge density wave ordering, which manifests as a breathing-mode distortion in the kagome layers. It has been suggested that such ordering derives from nesting between saddle points on the Fermi surface. In aid of the evolving understanding of this intriguing materials class, we present calculations of Fermi surface nesting and Lindhard susceptibility of CsV3Sb5. The breathing mode distortions appear to not display a simple link with Fermi surface nesting (FSN) and do not display the signatures of a Peierls-like transition. The FSN is agnostic to changes along kz and is only mildly impacted by small shifts of the Fermi level. The results suggest that FSN is largely independent of specific features in the saddle point.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Kornyakov, Ilya V., Victoria A. Vladimirova, Oleg I. Siidra et Sergey V. Krivovichev. « Expanding the Averievite Family, (MX)Cu5O2(T5+O4)2 (T5+ = P, V ; M = K, Rb, Cs, Cu ; X = Cl, Br) : Synthesis and Single-Crystal X-ray Diffraction Study ». Molecules 26, n^o 7 (24 mars 2021) : 1833. http://dx.doi.org/10.3390/molecules26071833.

Texte intégral

Résumé :

Averievite-type compounds with the general formula (MX)[Cu5O2(TO4)], where M = alkali metal, X = halogen and T = P, V, have been synthesized by crystallization from gases and structurally characterized for six different compositions: 1 (M = Cs; X = Cl; T = P), 2 (M = Cs; X = Cl; T = V), 3 (M = Rb; X = Cl; T = P), 4 (M = K; X = Br; T = P), 5 (M = K; X = Cl; T = P) and 6 (M = Cu; X = Cl; T = V). The crystal structures of the compounds are based upon the same structural unit, the layer consisting of a kagome lattice of Cu2+ ions and are composed from corner-sharing (OCu4) anion-centered tetrahedra. Each tetrahedron shares common corners with three neighboring tetrahedra, forming hexagonal rings, linked into the two-dimensional [O2Cu5]6+ sheets parallel to (001). The layers are interlinked by (T5+O4) tetrahedra (T5+ = V, P) attached to the bases of the oxocentered tetrahedra in a “face-to-face” manner. The resulting electroneutral 3D framework {[O2Cu5](T5+O4)2}0 possesses channels occupied by monovalent metal cations M+ and halide ions X−. The halide ions are located at the centers of the hexagonal rings of the kagome nets, whereas the metal cations are in the interlayer space. There are at least four different structure types of the averievite-type compounds: the P-3m1 archetype, the 2 × 2 × 1 superstructure with the P-3 space group, the monoclinically distorted 1 × 1 × 2 superstructure with the C2/c symmetry and the low-temperature P21/c superstructure with a doubled unit cell relative to the high-temperature archetype. The formation of a particular structure type is controlled by the interplay of the chemical composition and temperature. Changing the chemical composition may lead to modification of the structure type, which opens up the possibility to tune the geometrical parameters of the kagome net of Cu2+ ions.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Letrouit, A., S. Boudin et R. Retoux. « A strontium aluminium antimony oxide with Kagome layers : Sr1.5+xSb5+2−xAl5+xO14 (x≈0.21) ». Solid State Sciences 11, n^o 7 (juillet 2009) : 1183–86. http://dx.doi.org/10.1016/j.solidstatesciences.2009.02.019.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

17

Lee, Kyunghoon, M. Iqbal Bakti Utama, Salman Kahn, Appalakondaiah Samudrala, Nicolas Leconte, Birui Yang, Shuopei Wang et al. « Ultrahigh-resolution scanning microwave impedance microscopy of moiré lattices and superstructures ». Science Advances 6, n^o 50 (décembre 2020) : eabd1919. http://dx.doi.org/10.1126/sciadv.abd1919.

Texte intégral

Résumé :

Two-dimensional heterostructures composed of layers with slightly different lattice vectors exhibit new periodic structure known as moiré lattices, which, in turn, can support novel correlated and topological phenomena. Moreover, moiré superstructures can emerge from multiple misaligned moiré lattices or inhomogeneous strain distributions, offering additional degrees of freedom in tailoring electronic structure. High-resolution imaging of the moiré lattices and superstructures is critical for understanding the emerging physics. Here, we report the imaging of moiré lattices and superstructures in graphene-based samples under ambient conditions using an ultrahigh-resolution implementation of scanning microwave impedance microscopy. Although the probe tip has a gross radius of ~100 nm, spatial resolution better than 5 nm is achieved, which allows direct visualization of the structural details in moiré lattices and the composite super-moiré. We also demonstrate artificial synthesis of novel superstructures, including the Kagome moiré arising from the interplay between different layers.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Ishikawa, Hajime, Jun-ichi Yamaura, Yoshihiko Okamoto, Hiroyuki Yoshida, Gøran J. Nilsen et Zenji Hiroi. « A novel crystal polymorph of volborthite, Cu3V2O7(OH)2·2H2O ». Acta Crystallographica Section C Crystal Structure Communications 68, n^o 7 (13 juin 2012) : i41—i44. http://dx.doi.org/10.1107/s010827011202536x.

Texte intégral

Résumé :

A new polymorph of volborthite [tricopper(II) divanadium(V) heptaoxide dihydroxide dihydrate], Cu3V2O7(OH)2·2H2O, has been discovered in a single crystal prepared by hydrothermal synthesis. X-ray analysis reveals that the monoclinic structure has the space groupC2/cat room temperature, which is different from that of the previously reportedC2/mstructure. Both structures have Cu3O6(OH)2layers composed of edge-sharing CuO4(OH)2octahedra, with V2O7pillars and water molecules between the layers. The Cu atoms occupy two and three independent crystallographic sites in theC2/mandC2/cstructures, respectively, likely giving rise to different magnetic interactions between CuIIspins in the kagome lattices embedded in the Cu3O6(OH)2layers.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Zhang, Yiming, Xuanhao Yuan, Jian Hao, Meiling Xu et Yinwei Li. « Realizing high-temperature superconductivity in borophene with Dirac states assembled by kagome and honeycomb boron layers ». Materials Today Physics 35 (juin 2023) : 101144. http://dx.doi.org/10.1016/j.mtphys.2023.101144.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

20

Krüger, Biljana, Evgeny V. Galuskin, Irina O. Galuskina, Hannes Krüger et Yevgeny Vapnik. « Kahlenbergite KAl11O17, a new β-alumina mineral and Fe-rich hibonite from the Hatrurim Basin, the Negev desert, Israel ». European Journal of Mineralogy 33, n^o 4 (2 juillet 2021) : 341–55. http://dx.doi.org/10.5194/ejm-33-341-2021.

Texte intégral

Résumé :

Abstract. Kahlenbergite, ideally KAl11O17, and Fe-rich hibonite, CaAl10Fe2O19, are high-temperature minerals found in “olive” subunits of pyrometamorphic rocks, in the Hatrurim Basin, the Negev desert, Israel. The crystal structures of both minerals are refined using synchrotron radiation single-crystal diffraction data. The structure of kahlenbergite (P63/mmc; a=5.6486(1) Å; b=22.8970(3) Å; Z=2) exhibits triple spinel blocks and so-called R blocks. The spinel blocks show mixed layers with AlO6 octahedra and (Al0.56Fe0.44)O4 tetrahedra and kagome layers with (Al0.92Fe0.08)O6 octahedra. One-dimensional diffuse scattering observed parallel to c* implies stacking faults in the structure. Also, in one of the investigated kahlenbergite crystals additional reflections can be identified, which obviously belong to a second phase with a smaller lattice parameter c: Fe3+-rich hibonite. The structure of hibonite contains the same spinel blocks as kahlenbergite. The R blocks in hibonite contain Ca atoms, AlO5 bipyramids, and AlO6 octahedra, whereas the R blocks in kahlenbergite contain potassium atoms and AlO4 tetrahedra.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Dabić, Predrag, Volker Kahlenberg, Biljana Krüger, Marko Rodić, Sabina Kovač, Jovan Blanuša, Zvonko Jagličić, Ljiljana Karanović, Václav Petříček et Aleksandar Kremenović. « Low-temperature phase transition and magnetic properties of K3YbSi2O7 ». Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 77, n^o 4 (23 juillet 2021) : 584–93. http://dx.doi.org/10.1107/s2052520621006077.

Texte intégral

Résumé :

The new ambient-temperature hexagonal (space group P63 /mmc) polymorph of tripotassium ytterbium(III) disilicate (β-K3YbSi2O7) has been synthesized by the high-temperature flux method and subsequently structurally characterized. In the course of the temperature-dependent single-crystal diffraction experiments, a phase transformation of β-K3YbSi2O7 to a novel low-temperature orthorhombic phase (β′-K3YbSi2O7, space group Cmcm) has been observed at about 210 K. β-K3YbSi2O7 is isostructural with K3ErSi2O7, whereas β′-K3YbSi2O7 adopts a new type of structure. Both compounds can be built up from a regular alternation of layers of two types, which are parallel to the (001) plane. In the octahedral layer, YbO6 octahedra are isolated and linked by K1O6+3 polyhedra. The second, slightly thicker sorosilicate layer is formed by a combination of Si2O7 dimers and K2O6+3 polyhedra. The boundary between the layers is a pseudo-kagome oxide sheet based on 3.6.3.6 meshes. The phase transition is due to a tilt of the two SiO4 tetrahedra forming a single dimer which induces a decrease of the Si—O—Si angle between bridging Si—O bonds from 180° (dictated by symmetry in space group P63/mmc) to ≃164°. Magnetic characterization indicates that K3YbSi2O7 remains paramagnetic down to 2 K, showing no apparent influence of the phase transformation on its magnetic properties. Analysis of the magnetization data revealed the positions of the three lowest crystal field levels of the Yb3+ cations, as well as the corresponding projections of their angular momentum on the direction of the magnetic field.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Pei, Yongmao, Anmin Zeng, Licheng Zhou, Rubing Zhang et Kuixue Xu. « ELECTROMAGNETIC OPTIMAL DESIGN FOR DUAL-BAND RADOME WALL WITH ALTERNATING LAYERS OF STAGGERED COMPOSITE AND KAGOME LATTICE STRUCTURE ». Progress In Electromagnetics Research 122 (2012) : 437–52. http://dx.doi.org/10.2528/pier11101906.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

23

WULFF, L., et HK MUELLER-BUSCHBAUM. « ChemInform Abstract : Kagome Layers Connected by Isolated Trigonal SrO6 Prisms in the Strontium Manganate(IV) Tellurate(VI) : SrMnTeO6. » ChemInform 29, n^o 24 (22 juin 2010) : no. http://dx.doi.org/10.1002/chin.199824020.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

24

Wills, A. S. « Conventional and unconventional orderings in the jarosites ». Canadian Journal of Physics 79, n^o 11-12 (1 décembre 2001) : 1501–10. http://dx.doi.org/10.1139/p01-093.

Texte intégral

Résumé :

The jarosites make up the most studied family of Kagome anti-ferromagnets. The flexibility of the structure to substitution of the A and B ions allows a wide range of compositions to be synthesized with the general formula AB3(SO4)2(OH)6 (A = Na+, K+, Ag+, Rb+, H3O+, NH4+, 1/2Ba2+, and 1/2Pb2+; B = Fe3+, Cr3+, and V3+). Additional chemical tuning of the exchange between layers is also possible by substitution of the (SO4)2 groups by (SeO4)2 or (CrO4)2. Thus, a variety of S = 5/2, 3/2, and 1 systems can be engineered to allow study of the effects of frustration in both the classical and more quantum limits. Within this family both conventional long-ranged magnetic order and more exotic unconventional orderings have been found. This article reviews the different types of magnetic orderings that occur and examines some of the parameters that are their cause. PACS Nos.: 75.25+z, 75.30Et, 75.30Gw, 75.50Ee, 75.50Lk

Styles APA, Harvard, Vancouver, ISO, etc.

25

ENGLICH, U., C. FROMMEN et W. MASSA. « ChemInform Abstract : Jahn-Teller Ordering in Kagome-Type Layers of Compounds M2M′MnIII3F12 ( M : Rb, Cs ; M′ : Li, Na, K). » ChemInform 28, n^o 24 (3 août 2010) : no. http://dx.doi.org/10.1002/chin.199724026.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

26

Siidra, Oleg I., Michael S. Kozin, Wulf Depmeier, Roman A. Kayukov et Vadim M. Kovrugin. « Copper–lead selenite bromides : a new large family of compounds partly having Cu2+ substructures derivable from kagome nets ». Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 74, n^o 6 (30 novembre 2018) : 712–24. http://dx.doi.org/10.1107/s2052520618016542.

Texte intégral

Résumé :

Extensive experiments in the Pb–Cu–Se–O–Br system at 400°C yielded single crystals of nine new compounds (Cu2+Pb6(SeO3)4Br6, Cu2+Pb2(SeO3)2Br2, Cu2+ 3Pb2.4(SeO3)5Br0.8, Cu2+ 2Pb(SeO3)2Br2, Cu2+ 4Pb(SeO3)4Br2, [Cu2+ 9Pb2O4](Cu+Br2)(SeO3)4Br5, [Cu2+ 7PbO3](Cu+Br)0.35(SeO3)3Br4, [Cu2+ 8Pb2O4](Cu+Br)1.5(SeO3)4Br4, [Cu2+ 6Pb3O4](Cu+Pb1.27Br3.54)(SeO3)4Br2), all but one exhibiting new complex layered or open-framework architectures, organized via the host–guest principle. Five of these structures contain only bivalent copper: three with well ordered 2D structures and completely filled atomic positions, two structures have 3D frameworks. The four remaining compounds contain both, Cu2+ and Cu+, and comprise layers formed by edge- and vertex-sharing of oxocentered OCu2+ 4–n Pb n tetrahedra decorated with SeO3 2− and Br− anions. The interlayer spaces are filled by partially disordered Cu+–Br and Pb–Br associations. One remarkable feature of the latter group of compounds is the presence of tetrahedral (Cu2+)4 complexes with arrangements derivable from a kagome network.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Fujiwara, Kohei, Junya Ikeda, Shun Ito et Atsushi Tsukazaki. « Electrochemical thinning of Co kagome-lattice layers in ferromagnetic Co₃Sn₂S₂ thin films by bias-induced Co dissolution ». Journal of Applied Physics 133, n^o 12 (28 mars 2023) : 125302. http://dx.doi.org/10.1063/5.0134291.

Texte intégral

Résumé :

Solid–liquid interfaces made of functional inorganic materials and liquid electrolytes exhibit various interesting responses by applying an electric bias across the interface. Using an electric-double-layer device fabricated on a thin-film channel of magnetic Weyl semimetal Co3Sn2S2 with an ionic liquid gate electrolyte, we show that the conducting channel thickness can be effectively decreased by applying a negative gate voltage. The application of a gate voltage of −6 V at 250 K gives rise to an irreversible increase in the channel resistance. Transmission electron microscopy reveals that the thickness of the crystallized Co3Sn2S2 region is decreased by applying the negative bias, leaving a Co-poor disordered region on top of the Co3Sn2S2 layer. These results suggest that the preferential dissolution of Co is driven under the application of the negative bias, which leads to the disconnection of Co kagome-lattice layer that is mainly responsible for electrical conduction in Co3Sn2S2. Distinct from conventional bottom-up film growth approaches, this top-down thickness control enables us to examine the thickness dependence of the anomalous transport properties of Co3Sn2S2 in a single sample. The present finding will be useful for experimentally verifying the theoretically discussed ultrathin-film properties of the magnetic Weyl semimetal Co3Sn2S2.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Crichton, Wilson A., et Harald Müller. « Centennialite, CaCu3(OH)6Cl2.nH2O, n ≈ 0.7, a new kapellasite-like species, and a reassessment of calumetite ». Mineralogical Magazine 81, n^o 5 (octobre 2017) : 1105–24. http://dx.doi.org/10.1180/minmag.2016.080.157.

Texte intégral

Résumé :

AbstractThe new mineral centennialite (IMA 2013-110), CaCu3(OH)6Cl2·nH2O, was identified from three cotype specimens originating from the Centennial Mine, Houghton County, Michigan, USA, where it occurs as a secondary product, after acid water action upon supergene Cu mineralization in association with, and essentially indivisible from, other copper-containing minerals such as calumetite and atacamite family minerals. It forms as pale to azure blue encrustations, often taking a botryoidal form. Centennialite is trigonal, , a = 6.6606(9) Å, c = 5.8004(8) Å, V= 222.85(6) Å3, Z= 1. The strongest powder X-ray diffraction lines are dobs/Å [I%] (hkl), 5.799 [100] (001), 2.583 [75] (201), 2.886 [51] (111), 1.665 [20] (220), 1.605 [17] (023), 1.600 [15] (221), 1.444 [11] (222). The X-ray refined structure forms a kagome net of planar coordinated CuO4 units with Jahn-Teller coordinated Cl apices to form octahedra that edge-share to in-plane adjacent and flattened CaO6 octahedra, which are centred about the lattice origin. All oxygen sites are protonated and shared between one Ca-octahedron and one CuO4 planar unit. Three protonated sites are linked, by hydrogen-bonding to Cl sites, which sit on the triad axis. Each lattice has one Cl above and one below the Ca-Cu polyhedral plane. Consequently, the layers are stacked, along ⟨001⟩, with two Cl sites between layers. In addition to this kapellasite-like topology, an extra c/2 site is identified as being variably water-hosting and extends the coordination of the Ca-site to 8-fold, akin to the body-diagonal Pb-Cu sheet in murdochite. Centennialite conforms to the description of the ‘Unidentified Cu-Ca-Cl Mineral’ noted in Heinrich's Mineralogy of Michigan and is almost certainly identical to the supposed hexagonal basic calcium-copper hydroxychloride monohydrate of Erdös et al. (1981). We comment upon relationships between calumetite and centennialite and propose a substructure model for a synthetic calumetite-like phase that is related directly to centennialite.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Volkova, L. M., et D. V. Marinin. « Antiferromagnetic spin-frustrated layers of corner-sharing Cu4 tetrahedra on the kagome lattice in volcanic minerals Cu5O2(VO4)2(CuCl), NaCu5O2(SeO3)2Cl3, and K2Cu5Cl8(OH)4·2H2O ». Journal of Physics : Condensed Matter 30, n^o 42 (25 septembre 2018) : 425801. http://dx.doi.org/10.1088/1361-648x/aade0b.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

30

Whangbo, Myung-Hwan, Hyun-Joo Koo, Eva Brücher, Pascal Puphal et Reinhard K. Kremer. « Absence of Spin Frustration in the Kagomé Layers of Cu2+ Ions in Volborthite Cu3V2O7(OH)2·2H2O and Observation of the Suppression and Re-Entrance of Specific Heat Anomalies in Volborthite under an External Magnetic Field ». Condensed Matter 7, n^o 1 (28 février 2022) : 24. http://dx.doi.org/10.3390/condmat7010024.

Texte intégral

Résumé :

We determined the spin exchanges between the Cu2+ ions in the kagomé layers of volborthite, Cu3V2O7(OH)2·2H2O, by performing the energy-mapping analysis based on DFT+U calculations, to find that the kagomé layers of Cu2+ ions are hardly spin-frustrated, and the magnetic properties of volborthite below ~75 K should be described by very weakly interacting antiferromagnetic uniform chains made up of effective S = 1/2 pseudospin units. This conclusion was verified by synthesizing single crystals of not only Cu3V2O7(OH)2·2H2O but also its deuterated analogue Cu3V2O7(OD)2·2D2O and then by investigating their magnetic susceptibilities and specific heats. Each kagomé layer consists of intertwined two-leg spin ladders with rungs of linear spin trimers. With the latter acting as S = 1/2 pseudospin units, each two-leg spin ladder behaves as a chain of S = 1/2 pseudospins. Adjacent two-leg spin ladders in each kagomé layer interact very weakly, so it is required that all nearest-neighbor spin exchange paths of every two-leg spin ladder remain antiferromagnetically coupled in all spin ladder arrangements of a kagomé layer. This constraint imposes three sets of entropy spectra with which each kagomé layer can exchange energy with the surrounding on lowering the temperature below ~1.5 K and on raising the external magnetic field B. We discovered that the specific heat anomalies of volborthite observed below ~1.5 K at B = 0 are suppressed by raising the magnetic field B to ~4.2 T, that a new specific heat anomaly occurs when B is increased above ~5.5 T, and that the imposed three sets of entropy spectra are responsible for the field-dependence of the specific heat anomalies.

Styles APA, Harvard, Vancouver, ISO, etc.

31

McGuire, Michael A., Eleanor M. Clements, Qiang Zhang et Satoshi Okamoto. « Double-Layer Kagome Metals Pt3Tl2 and Pt3In2 ». Crystals 13, n^o 5 (17 mai 2023) : 833. http://dx.doi.org/10.3390/cryst13050833.

Texte intégral

Résumé :

The connectivity and inherent frustration of the kagome lattice can produce interesting electronic structures and behaviors in compounds containing this structural motif. Here we report the properties of Pt3X2 (X = In and Tl) that adopt a double-layer kagome net structure related to that of the topologically nontrivial high-temperature ferromagnet Fe3Sn2 and the density wave hosting compound V3Sb2. We examined the structural and physical properties of single crystal Pt3Tl2 and polycrystalline Pt3In2 using X-ray and neutron diffraction, magnetic susceptibility, heat capacity, and electrical transport measurements, along with density functional theory calculations of the electronic structure. Our calculations show that Fermi levels lie in pseudogaps in the densities of states with several bands contributing to transport, and this is consistent with our Hall effect, magnetic susceptibility, and heat capacity measurements. Although electronic dispersions, characteristic of simple kagome nets with nearest-neighbor hopping, are not clearly seen, likely due to the extended nature of the Pt 5d states, we do observe moderately large and non-saturating magnetoresistance values and quantum oscillations in the magnetoresistance and magnetization associated with the kagome nets of Pt.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Zhang, Mengsi, Zhiying Zhao, Wanwan Zhang, Jinyang Li, Xiaoying Huang et Zhangzhen He. « Pb(OF)Cu3(SeO3)2(NO3) : a selenite fluoride nitrate with a breathing kagomé lattice ». Chemical Communications 56, n^o 80 (2020) : 11965–68. http://dx.doi.org/10.1039/d0cc03684f.

Texte intégral

Résumé :

A spin-1/2 breathing kagomé compound Pb(OF)Cu₃(SeO₃)₂(NO₃) exhibits ferromagnetic interactions inside the layers and antiferromagnetic interactions between the neighboring layers.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Li, Zhijun, Xinlong Dong, Dou Chen, Yan Jiang et Xuehua Li. « Blast-Resistant Performance of Steel Petrochemical Control Room with 3D-Kagome Sandwich Wall ». Sustainability 16, n^o 10 (9 mai 2024) : 3967. http://dx.doi.org/10.3390/su16103967.

Texte intégral

Résumé :

As the control brain of the petrochemical plant, blast-resistant performance requirements are important for the sustainability of the petrochemical control room and should be guaranteed when the vapor cloud explosion occurs in the petrochemical production process. The 3D-Kagome truss core sandwich structure is a kind of blast-resistant material with high energy absorption and recycling. Considering the influential factors of the radius of the truss core rod and thickness of the upper and lower panels, in this paper, the blast-resistant performance of a real steel petrochemical control room with a 3D-Kagome truss core sandwich wall was analyzed. With the optimization goal of plastic deformation energy and panel displacement, the optimal wall thickness and radius of the truss core rod were obtained. The optimized blast-resistant walls were assembled, and the dynamic response of the steel petrochemical control room with the 3D-Kagome truss core sandwich blast-resistant wall was analyzed. The simulation results indicate that the truss core layer is ineffective in dissipating blast energy when the radius ratio of the truss core rod exceeds 2.7% of the total wall thickness. Moreover, as the thickness of the upper and lower panels increases from 0.5 cm to 3 cm, the proportion of plastic deformation energy in the truss core layer gradually rises from 55% to 95%, stabilizing at around 90%. The optimal configuration for blast resistance is achieved when the panel thickness ratio is 6.7% of the total wall thickness; the truss core rod radius ratio is 2.7% of the total thickness. This study establishes the effectiveness of the optimized 3D-Kagome sandwich wall as a blast-resistant solution for steel petrochemical control rooms.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Kshetrimayum, Augustine, Christian Balz, Bella Lake et Jens Eisert. « Tensor network investigation of the double layer Kagome compound Ca10Cr7O28 ». Annals of Physics 421 (octobre 2020) : 168292. http://dx.doi.org/10.1016/j.aop.2020.168292.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

35

Grey, Ian E. « Kagomé networks of octahedrally coordinated metal atoms in minerals : Relating different mineral structures through octahedral tilting ». Mineralogical Magazine 84, n^o 5 (17 septembre 2020) : 640–52. http://dx.doi.org/10.1180/mgm.2020.72.

Texte intégral

Résumé :

AbstractKagomé nets of corner-connected triangles of atoms occur in diverse minerals, from the {111} anion arrays in perovskite-group minerals to natural metallic alloys like auricupride, AuCu3, to the cation layers in atacamite-group minerals. We review here two- and three-dimensional kagomé networks in minerals where the kagomé node atoms are octahedrally coordinated in hexagonal tungsten bronze (HTB) arrays. Octahedral tilting, coupled with capping of the apical anions of the triangular groupings of octahedra in the HTB layers, gives rise to several important mineral groups, including pyrochlores, alunite-supergroup minerals, zirconolite and weberite polytypes and spinel-group minerals, as a function of the magnitude and type of the octahedral tilting.

Styles APA, Harvard, Vancouver, ISO, etc.

36

M. S, Hema, Abhilash V, Tharun V et Madukar Reddy. « Weed Detection Using Convolutional Neural Network ». BOHR International Journal of Intelligent Instrumentation and Computing 1, n^o 1 (2021) : 39–42. http://dx.doi.org/10.54646/bijiiac.007.

Texte intégral

Résumé :

Precision agriculture relies heavily on information technology, which also aids agronomists in their work. Weeds usually grow alongside crops, reducing the production of that crop. Weeds are controlled by herbicides. The pesticide may harm the crop as well if the type of weed isn’t identified. In order to control weeds on farms, it is required to identify and classify them. Convolutional Network or CNN, a deep learning-based computer vision technology, is used to evaluate images. A methodology is proposed to detect weed using convolutional neural networks. There were two primary phases in this proposed methodology. The first phase is image collection and labeling, in which the features for images to be labeled for the base images are extracted. In second phase to build the convolutional neural network model is constructed by 20 layers to detect the weed. CNN architecture has three layers namely convolutional layer, pooling layer and dense layer. The input image is given to convolutional layer to extract the features from the image. The features are given to pooling layer to compress the image to reduce the computational complexity. The dense layer is used for final classification. The performance of the proposed methodology is assessed using agricultural dataset images taken from Kaggle database.

Styles APA, Harvard, Vancouver, ISO, etc.

37

V, Tharun, Madukar Reddy D, M. S. Hema et V. Abhilash. « Weed Detection Using Convolutional Neural Network ». BOHR International Journal of Computer Science 1, n^o 1 (2023) : 47–50. http://dx.doi.org/10.54646/bijcs.2022.08.

Texte intégral

Résumé :

Precision agriculture relies heavily on information technology, which also aids agronomists in their work. Weeds usually grow alongside crops, reducing the production of that crop. They are controlled by herbicides. The pesticide may harm the crop as well if the type of weed is not identified. To control weeds on farms, it is required to identify and classify them. A convolutional network or CNN, a deep learning-based computer vision technology, is used to evaluate images. A methodology is proposed to detect weeds using convolutional neural networks. There were two primary phases in this proposed methodology. The first phase is image collection and labeling, in which the features for images to be labeled for the base images are extracted. In the second phase, the convolutional neural network model is constructed by 20 layers to detect the weed. CNN architecture has three layers, namely, the convolutional layer, the pooling layer, and the dense layer. The input image is given to a convolutional layer to extract the features from the image. The features are given to the pooling layer to compress the image to reduce the computational complexity. The dense layer is used for final classification. The performance of the proposed methodology is assessed using agricultural dataset images taken from the Kaggle database.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Weihrich, Richard, Wenjie Yan, Jan Rothballer, Philipp Peter, Stefan Michael Rommel, Sebastian Haumann, Florian Winter, Christian Schwickert et Rainer Pöttgen. « Tuneable anisotropy and magnetism in Sn2Co3S2−xSex – probed by 119Sn Mößbauer spectroscopy and DFT studies ». Dalton Transactions 44, n^o 36 (2015) : 15855–64. http://dx.doi.org/10.1039/c5dt02036k.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

39

Wang, Jinfeng, et Xuegang Wang. « Two new methods for facial expression recognition using Convolutional Neural Networks ». Journal of Physics : Conference Series 2031, n^o 1 (1 septembre 2021) : 012023. http://dx.doi.org/10.1088/1742-6596/2031/1/012023.

Texte intégral

Résumé :

Abstract In this research, we propose two novel methods for facial expression recognition to improve the accuracy of recognition. The first of our novel approach is to add the Batch Normalization (BN) layer to the CNN model, and the second of the novel approach is to preprocess the image before image training, such as rotating image, cropping the image and adding Gaussian noise in the picture, especially it is beneficial for unbalanced classifications. Our model consists of 3 CNN layers, 3 BN layers, three average-pooling layers, and three fully-connected layers; our model has a satisfying performance on the prediction category after adopting the two methods mentioned above. Our CNN model is trained and tested with Kaggle facial expression recognition challenge databases. The implemented system can automatically recognize seven expressions in real-time: anger, disgust, fear, happiness, neutral, sadness, and sur-prise. The experimental results demonstrate the effectiveness of our proposed approach.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Siswanto, Joko, Benny Daniawan, Haryani Haryani et Pipit Rusmandani. « Testing Of Deep Learning-Based LSTM Model For Number Of Road Accidents Predicting ». Jurnal Sains, Nalar, dan Aplikasi Teknologi Informasi 3, n^o 3 (3 juillet 2024) : 95–103. http://dx.doi.org/10.20885/snati.v3.i3.37.

Texte intégral

Résumé :

Many have used the prediction of the number of road accidents, but it is still rare to find those who use and test prediction models that are not suitable. Predictive models that have been used to predict road accidents have proven successful, but have not provided model testing with data that is different from the deep learning approach. The LSTM model test is proposed to be tested with 5 different datasets from Kaggle and 3 hidden layer variations. The test results of the LSTM model are that with variations of 4 hidden layers it can achieve higher accuracy results than those without hidden layers and 2 hidden layers. The results are obtained from stability with the lowest average MSLE value and relatively balanced average time. Deep learning-based LSTM model testing was carried out to ensure and prove the stability of the model for predicting the number of road accidents in the future. Stakeholders can predict the number of road accidents using the resulting prediction model.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Smart, Megan M., Tiffany M. Smith Pellizzeri, Gregory Morrison, Colin D. McMillen, Hans-Conrad zur Loye et Joseph W. Kolis. « Ferrite Materials Containing Kagomé Layers : Chemistry of Ba2Fe11Ge2O22 and K2Co4V9O22 Hexaferrites ». Chemistry of Materials 33, n^o 7 (1 avril 2021) : 2258–66. http://dx.doi.org/10.1021/acs.chemmater.0c03852.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

42

Phani, A. Srikantha, et Norman A. Fleck. « Elastic Boundary Layers in Two-Dimensional Isotropic Lattices ». Journal of Applied Mechanics 75, n^o 2 (27 février 2008). http://dx.doi.org/10.1115/1.2775503.

Texte intégral

Résumé :

The phenomenon of elastic boundary layers under quasistatic loading is investigated using the Floquet–Bloch formalism for two-dimensional, isotropic, periodic lattices. The elastic boundary layer is a region of localized elastic deformation, confined to the free edge of a lattice. Boundary layer phenomena in three isotropic lattice topologies are investigated: the semiregular Kagome lattice, the regular hexagonal lattice, and the regular fully triangulated lattice. The boundary layer depth is on the order of the strut length for the hexagonal and the fully triangulated lattices. For the Kagome lattice, the depth of boundary layer scales inversely with the relative density. Thus, the boundary layer in a Kagome lattice of low relative density spans many cells.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Gibson, Quinn D., Dongsheng Wen, Hai Lin, Marco Zanella, Luke M. Daniels, Craig M. Robertson, John B. Claridge, Jonathan Alaria, Matthew S. Dyer et Matthew J. Rosseinsky. « Control of Polarity in Kagome‐NiAs Bismuthides ». Angewandte Chemie International Edition, 12 mars 2024. http://dx.doi.org/10.1002/anie.202403670.

Texte intégral

Résumé :

A 2×2×1 superstructure of the P63/mmc NiAs structure is reported in which kagome nets are stabilized in the octahedral transition metal layers of the compounds Ni0.7Pd0.2Bi, Ni0.6Pt0.4Bi, and Mn0.99Pd0.01Bi. The ordered vacancies that yield the true hexagonal kagome motif lead to filling of trigonal bipyramidal interstitial sites with the transition metal in this family of “kagome‐NiAs” type materials. Further ordering of vacancies within these interstitial layers can be compositionally driven to simultaneously yield kagome‐connected layers and a net polarization along the c axes in Ni0.9Bi and Ni0.79Pd0.08Bi, which adopt Fmm2 symmetry. The polar and non‐polar materials exhibit different electronic transport behaviour, reflecting the tuneability of both structure and properties within the NiAs‐type bismuthide materials family.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Gibson, Quinn D., Dongsheng Wen, Hai Lin, Marco Zanella, Luke M. Daniels, Craig M. Robertson, John B. Claridge, Jonathan Alaria, Matthew S. Dyer et Matthew J. Rosseinsky. « Control of Polarity in Kagome‐NiAs Bismuthides ». Angewandte Chemie, 12 mars 2024. http://dx.doi.org/10.1002/ange.202403670.

Texte intégral

Résumé :

A 2×2×1 superstructure of the P63/mmc NiAs structure is reported in which kagome nets are stabilized in the octahedral transition metal layers of the compounds Ni0.7Pd0.2Bi, Ni0.6Pt0.4Bi, and Mn0.99Pd0.01Bi. The ordered vacancies that yield the true hexagonal kagome motif lead to filling of trigonal bipyramidal interstitial sites with the transition metal in this family of “kagome‐NiAs” type materials. Further ordering of vacancies within these interstitial layers can be compositionally driven to simultaneously yield kagome‐connected layers and a net polarization along the c axes in Ni0.9Bi and Ni0.79Pd0.08Bi, which adopt Fmm2 symmetry. The polar and non‐polar materials exhibit different electronic transport behaviour, reflecting the tuneability of both structure and properties within the NiAs‐type bismuthide materials family.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Riberolles, S. X. M., Tyler J. Slade, Tianxiong Han, Bing Li, D. L. Abernathy, P. C. Canfield, B. G. Ueland, P. P. Orth, Liqin Ke et R. J. McQueeney. « Chiral and flat-band magnetic quasiparticles in ferromagnetic and metallic kagome layers ». Nature Communications 15, n^o 1 (21 février 2024). http://dx.doi.org/10.1038/s41467-024-45841-8.

Texte intégral

Résumé :

AbstractMagnetic kagome metals are a promising platform to develop unique quantum transport and optical phenomena caused by the interplay between topological electronic bands, strong correlations, and magnetic order. This interplay may result in exotic quasiparticles that describe the coupled electronic and spin excitations on the frustrated kagome lattice. Here, we observe novel elementary magnetic excitations within the ferromagnetic Mn kagome layers in TbMn6Sn6 using inelastic neutron scattering. We observe sharp, collective acoustic magnons and identify flat-band magnons that are localized to a hexagonal plaquette due to the special geometry of the kagome layer. Surprisingly, we observe another type of elementary magnetic excitation; a chiral magnetic quasiparticle that is also localized on a hexagonal plaquette. The short lifetime of localized flat-band and chiral quasiparticles suggest that they are hybrid excitations that decay into electronic states.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Li, Man, Huan Ma, Rui Lou et Shancai Wang. « Electronic band structures of topological kagome materials ». Chinese Physics B, 14 novembre 2024. http://dx.doi.org/10.1088/1674-1056/ad925d.

Texte intégral

Résumé :

Abstract The kagome lattice has garnered significant attention due to its ability to host quantum spin Fermi liquid states. Recently, the combination of unique lattice geometry, electron-electron correlations, and adjustable magnetism in solid kagome materials has led to the discovery of numerous fascinating quantum properties. These include unconventional superconductivity, charge and spin density waves (CDW/SDW), pair density waves (PDW), and Chern insulator phases. These emergent states are closely associated with the distinctive characteristics of the kagome lattice's electronic structure, such as van Hove singularities, Dirac fermions, and flat bands, which can exhibit exotic quasi-particle excitations under different symmetries and magnetic conditions. Recently, various quantum kagome materials have been developed, typically consisting of kagome layers stacked along the $z$-axis with atoms either filling the geometric centers of the kagome lattice or embedded between the layers. In this topical review, we begin by introducing the fundamental properties of several kagome materials. To gain an in-depth understanding of the relationship between topology and correlation, we then discuss the complex phenomena observed in these systems. These include the simplest kagome metal $T_3X$, kagome intercalation metal $TX$, and the ternary compounds $AT_6X_6$ and $RT_3X_5$ ($A$ = Li, Mg, Ca, or rare earth; $T$ = V, Cr, Mn, Fe, Co, Ni; $X$ = Sn, Ge; $R$ = K, Rb, Cs). Finally, we provide a perspective on future experimental work in this field.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Zhang, Huimin, Basu Dev Oli, Qiang Zou, Xu Guo, Zhengfei Wang et Lian Li. « Visualizing symmetry-breaking electronic orders in epitaxial Kagome magnet FeSn films ». Nature Communications 14, n^o 1 (4 octobre 2023). http://dx.doi.org/10.1038/s41467-023-41831-4.

Texte intégral

Résumé :

AbstractKagome lattice hosts a plethora of quantum states arising from the interplay of topology, spin-orbit coupling, and electron correlations. Here, we report symmetry-breaking electronic orders tunable by an applied magnetic field in a model Kagome magnet FeSn consisting of alternating stacks of two-dimensional Fe3Sn Kagome and Sn2 honeycomb layers. On the Fe3Sn layer terminated FeSn thin films epitaxially grown on SrTiO3(111) substrates, we observe trimerization of the Kagome lattice using scanning tunneling microscopy/spectroscopy, breaking its six-fold rotational symmetry while preserving the translational symmetry. Such a trimerized Kagome lattice shows an energy-dependent contrast reversal in dI/dV maps, which is significantly enhanced by bound states induced by Sn vacancy defects. This trimerized Kagome lattice also exhibits stripe modulations that are energy-dependent and tunable by an applied in-plane magnetic field, indicating symmetry-breaking nematicity from the entangled magnetic and charge degrees of freedom in antiferromagnet FeSn.

Styles APA, Harvard, Vancouver, ISO, etc.

48

Yang, T. Y., Q. Wan, J. P. Song, Z. Du, J. Tang, Z. W. Wang, N. C. Plumb et al. « Fermi-level flat band in a kagome magnet ». Quantum Frontiers 1, n^o 1 (18 novembre 2022). http://dx.doi.org/10.1007/s44214-022-00017-7.

Texte intégral

Résumé :

AbstractThe band structure in a kagome lattice can naturally exhibit flat band, Dirac cones, and van Hove singularity, enabling rich interplays between correlation and topology. However, the flat band is rarely detected just at the Fermi level in kagome materials, which would be crucial to realize emergent flat band physics. Here, combining angle-resolved photoemission spectroscopy, transport measurements and first-principles calculation, we observe a striking Fermi-level flat band in paramagnetic YCr6Ge6 as a typical signature of electronic kagome lattice. We explicitly unveil that orbital character plays an essential role to realize electronic kagome lattice in crystals with transition-metal kagome layers. We further engineer this material with magnetic rare earth elements to break the time-reversal symmetry of the Fermi-level kagome flat band. Our work establishes a Fermi-level flat band in a kagome magnet as an exciting quantum platform.

Styles APA, Harvard, Vancouver, ISO, etc.

49

de Rojas, Julius, Del Atkinson et Adekunle Olusola Adeyeye. « Tailoring magnon modes by extending square, kagome, and trigonal spin ice lattices vertically via interlayer coupling of trilayer nanomagnets ». Journal of Physics : Condensed Matter, 28 juin 2024. http://dx.doi.org/10.1088/1361-648x/ad5d3f.

Texte intégral

Résumé :

Abstract In this work high-frequency magnetization dynamics and statics of artificial spin-ice lattices with different geometric nanostructure array configurations are studied where the individual nanostructures are composed of ferromagnetic/non-magnetic/ferromagnetic trilayers with different non-magnetic thicknesses. These thickness variations enable additional control over the magnetic interactions within the spin-ice lattice that directly impacts the resulting magnetization dynamics and the associated magnonic modes. Specifically the geometric arrangements studied are square, kagome and trigonal spin ice configurations, where the individual lithographically patterned nanomagnets are trilayers, made up of two magnetic layers of $\text{Ni}_{81}\text{Fe}_{19}$ of 30 nm and 70 nm thickness respectively, separated by a non-magnetic copper layer of either 2 nm or 40 nm. We show that coupling via the magnetostatic interactions between the ferromagnetic layers of the nanomagnets within square, kagome and trigonal spin-ice lattices offers fine-control over magnetization states and magnetic resonant modes. In particular, the kagome and trigonal lattices allow tuning of an additional mode and the spacing between multiple resonance modes, increasing functionality beyond square lattices. These results demonstrate the ability to move beyond quasi-2D single magnetic layer nanomagnetics via control of the vertical interlayer interactions in spin ice arrays. This additional control enables multi-mode magnonic programmability of the resonance spectra, which has potential for magnetic metamaterials for microwave or information processing applications.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Ding, Jianyang, Zhonghao Liu, Ningning Zhao, Zicheng Tao, Zhe Huang, Zhicheng Jiang, Yichen Yang et al. « Kagome surface states and weak electronic correlation in vanadium-kagome metals ». Journal of Physics : Condensed Matter, 28 juin 2023. http://dx.doi.org/10.1088/1361-648x/ace2a2.

Texte intégral

Résumé :

Abstract RV6Sn6 (R = Y and lanthanides) with two-dimensional vanadium-kagome surface states is an ideal platform to investigate kagome physics and manipulate the kagome features to realize novel phenomena. Utilizing the micron-scale spatially resolved angle-resolved photoemission spectroscopy and ﬁrst-principles calculations, we report a systematical study of the electronic structures of RV6Sn6 (R = Gd, Tb, and Lu) on the two cleaved surfaces, i.e., the V- and RSn1-terminated (001) surfaces. The calculated bands without any renormalization match well with the main ARPES dispersive features, indicating the weak electronic correlation in this system. We observe ’W’-like kagome surface states around the Brillouin zone corners showing R-element-dependent intensities, which is probably due to various coupling strengths between V and RSn1 layers. Our ﬁnding suggests an avenue for tuning electronic states by interlayer coupling based on two-dimensional kagome lattices.

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Kagome layers »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres