Articles de revues : « Spin-orbit Coupled Electronic Systems »

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Marković, Igor, Matthew D. Watson, Oliver J. Clark, Federico Mazzola, Edgar Abarca Morales, Chris A. Hooley, Helge Rosner et al. « Electronically driven spin-reorientation transition of the correlated polar metal Ca3Ru2O7 ». Proceedings of the National Academy of Sciences 117, n^o 27 (23 juin 2020) : 15524–29. http://dx.doi.org/10.1073/pnas.2003671117.

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The interplay between spin–orbit coupling and structural inversion symmetry breaking in solids has generated much interest due to the nontrivial spin and magnetic textures which can result. Such studies are typically focused on systems where large atomic number elements lead to strong spin–orbit coupling, in turn rendering electronic correlations weak. In contrast, here we investigate the temperature-dependent electronic structure ofCa3Ru2O7, a4doxide metal for which both correlations and spin–orbit coupling are pronounced and in which octahedral tilts and rotations combine to mediate both global and local inversion symmetry-breaking polar distortions. Our angle-resolved photoemission measurements reveal the destruction of a large hole-like Fermi surface upon cooling through a coupled structural and spin-reorientation transition at 48 K, accompanied by a sudden onset of quasiparticle coherence. We demonstrate how these result from band hybridization mediated by a hidden Rashba-type spin–orbit coupling. This is enabled by the bulk structural distortions and unlocked when the spin reorients perpendicular to the local symmetry-breaking potential at the Ru sites. We argue that the electronic energy gain associated with the band hybridization is actually the key driver for the phase transition, reflecting a delicate interplay between spin–orbit coupling and strong electronic correlations and revealing a route to control magnetic ordering in solids.

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Berger, Michael, Dominik Schulz et Jamal Berakdar. « Spin-Resolved Quantum Scars in Confined Spin-Coupled Two-Dimensional Electron Gas ». Nanomaterials 11, n^o 5 (11 mai 2021) : 1258. http://dx.doi.org/10.3390/nano11051258.

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Quantum scars refer to an enhanced localization of the probability density of states in the spectral region with a high energy level density. Scars are discussed for a number of confined pure and impurity-doped electronic systems. Here, we studied the role of spin on quantum scarring for a generic system, namely a semiconductor-heterostructure-based two-dimensional electron gas subjected to a confining potential, an external magnetic field, and a Rashba-type spin-orbit coupling. Calculating the high energy spectrum for each spin channel and corresponding states, as well as employing statistical methods known for the spinless case, we showed that spin-dependent scarring occurs in a spin-coupled electronic system. Scars can be spin mixed or spin polarized and may be detected via transport measurements or spin-polarized scanning tunneling spectroscopy.

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HJELM, ANDERS, JOAKIM TRYGG, OLLE ERIKSSON, BÖRJE JOHANSSON et JOHN M. WILLS. « ORBITAL PARAMAGNETISM IN METALLIC SYSTEMS WITH LARGE ANGULAR MOMENTA ». International Journal of Modern Physics B 09, n^o 21 (30 septembre 1995) : 2735–51. http://dx.doi.org/10.1142/s0217979295001026.

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We demonstrate that the field induced spin and orbital moments in paramagnetic metals in general are parallel, since the Zeeman energy overcomes the spin-orbit energy that is in favor of an antiparallel arrangement when the electronic shell is less than half-filled. In the early actinides, however, the spin-orbit energy becomes sufficiently strong to approach the border where the moments can couple antiparallel. This results in peculiar magnetic states for α-Pu and some uranium compounds, where the spin moments are antiparallel to the applied field and the magnetic response dominated by the orbital character, and consequently these systems display unusual spin densities and magnetic form factors.

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Kochelap, V. A., et A. E. Belyaev. « To 95-th birthday of Professor E.I. Rashba (looking back ones again) ». Semiconductor Physics, Quantum Electronics and Optoelectronics 25, n^o 3 (6 octobre 2022) : 235–39. http://dx.doi.org/10.15407/spqeo25.03.235.

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The theory of spin-orbit interaction, developed by E.I. Rashba more than 30 years ago, stimulated the rapid development of a new discipline – spintronics – the physics of processes and devices based on the control of spins. The paper summarizes achievements of Prof. Rashba in the early stage of his scientific researches, particularly those, which were performed in Ukraine. Among them, prediction of electric dipole spin resonance (EDSR), phase transitions in spin-orbit coupled systems driven by change of the Fermi surface topology, giant oscillator strength of impurity excitons, and coexistence of free and self-trapped excitons. Solid state physics is the basis of contemporary electronics and optoelectronics. Various electronic, optical, acoustical and other effects and processes in solid define performances of modern solid state devices. Multitude of groups and thousands researchers are involved in discovering, study and using relevant new phenomena. Among them, Professor Emmanuel Rashba with his outstanding results in physics of crystals is seen (rises) as a profound personality. His contribution in almost all branches of solid state physics cannot be exaggerated, some of his results have found important applications. Prof. E.I. Rashba is known as one of the leading theorists in Ukraine, in Soviet Union, and he continued the successful career in United States. Although many years have already passed, scientific community in Ukraine remembers Prof. E.I. Rashba and thankfully appreciates his impact to formation of condensed matter researches in our country. This short text is devoted to Prof. E.I. Rashba and is written on the occasion of his birthday.

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Shah, Muzamil. « Probing topological quantum phase transitions via photonic spin Hall effects in spin-orbit coupled 2D quantum materials ». Journal of Physics D : Applied Physics 55, n^o 10 (6 décembre 2021) : 105105. http://dx.doi.org/10.1088/1361-6463/ac3c76.

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Abstract Topological photonics is an emerging field in photonics in which various topological and geometrical ideas are used to manipulate and control the behavior of light photons. The interplay between topological matter and the spin degree of freedom of photons provides new opportunities for achieving spin-based photonics applications. In this paper, the photonic spin Hall effect (PSHE) of reflected light from the surface of the topological silicene quantum systems subjected to external electric and radiation fields in the terahertz regime is theoretically investigated. By tuning the external electric and the applied laser fields, we can drive the silicenic system through different topological quantum phase transitions. We demonstrate that the in-plane and transverse spatial spin dependent shifts exhibit extreme values near Brewster’s angles and away from the optical transition frequencies. We reveal that the photonic spin Hall shifts are sensitive to the spin and valley indices as well as to the number of closed gaps. We believe that the spin and valley-resolved PSHE will greatly impact the research in spinoptics, spintronics, and valleytronics.

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Fiorentini, Simone, Nils Petter Jørstad, Johannes Ender, Roberto Lacerda de Orio, Siegfried Selberherr, Mario Bendra, Wolfgang Goes et Viktor Sverdlov. « Finite Element Approach for the Simulation of Modern MRAM Devices ». Micromachines 14, n^o 5 (22 avril 2023) : 898. http://dx.doi.org/10.3390/mi14050898.

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Because of their nonvolatile nature and simple structure, the interest in MRAM devices has been steadily growing in recent years. Reliable simulation tools, capable of handling complex geometries composed of multiple materials, provide valuable help in improving the design of MRAM cells. In this work, we describe a solver based on the finite element implementation of the Landau–Lifshitz–Gilbert equation coupled to the spin and charge drift-diffusion formalism. The torque acting in all layers from different contributions is computed from a unified expression. In consequence of the versatility of the finite element implementation, the solver is applied to switching simulations of recently proposed structures based on spin-transfer torque, with a double reference layer or an elongated and composite free layer, and of a structure combining spin-transfer and spin-orbit torques.

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Polley, Debanjan, Akshay Pattabi, Jyotirmoy Chatterjee, Sucheta Mondal, Kaushalya Jhuria, Hanuman Singh, Jon Gorchon et Jeffrey Bokor. « Progress toward picosecond on-chip magnetic memory ». Applied Physics Letters 120, n^o 14 (4 avril 2022) : 140501. http://dx.doi.org/10.1063/5.0083897.

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We offer a perspective on the prospects of ultrafast spintronics and opto-magnetism as a pathway to high-performance, energy-efficient, and non-volatile embedded memory in digital integrated circuit applications. Conventional spintronic devices, such as spin-transfer-torque magnetic-resistive random-access memory (STT-MRAM) and spin–orbit torque MRAM, are promising due to their non-volatility, energy-efficiency, and high endurance. STT-MRAMs are now entering into the commercial market; however, they are limited in write speed to the nanosecond timescale. Improvement in the write speed of spintronic devices can significantly increase their usefulness as viable alternatives to the existing CMOS-based devices. In this article, we discuss recent studies that advance the field of ultrafast spintronics and opto-magnetism. An optimized ferromagnet–ferrimagnet exchange-coupled magnetic stack, which can serve as the free layer of a magnetic tunnel junction (MTJ), can be optically switched in as fast as ∼3 ps. Integration of ultrafast magnetic switching of a similar stack into an MTJ device has enabled electrical readout of the switched state using a relatively larger tunneling magnetoresistance ratio. Purely electronic ultrafast spin–orbit torque induced switching of a ferromagnet has been demonstrated using ∼6 ps long charge current pulses. We conclude our Perspective by discussing some of the challenges that remain to be addressed to accelerate ultrafast spintronics technologies toward practical implementation in high-performance digital information processing systems.

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Cooper, David L., Joseph Gerratt et Mario Raimondi. « The Spin-coupled Approach to Electronic Structure ». Molecular Simulation 4, n^o 5 (février 1990) : 293–312. http://dx.doi.org/10.1080/08927029008022393.

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Wang, C. M., et M. Q. Pang. « Optical out-of-plane spin polarization and charge conductivities in spin-orbit-coupled systems in the presence of an in-plane magnetic field ». European Physical Journal B 74, n^o 1 (4 février 2010) : 19–25. http://dx.doi.org/10.1140/epjb/e2010-00040-7.

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Chen, Xiong-wei, Zhi-gui Deng, Xiao-xi Xu, Shu-lan Li, Zhi-wei Fan, Zhao-pin Chen, Bin Liu et Yong-yao Li. « Nonlinear modes in spatially confined spin–orbit-coupled Bose–Einstein condensates with repulsive nonlinearity ». Nonlinear Dynamics 101, n^o 1 (27 juin 2020) : 569–79. http://dx.doi.org/10.1007/s11071-020-05692-6.

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Chauhan, Prashant, Candice Thomas, Tyler Lindemann, Geoffrey C. Gardner, J. Gukelberger, M. J. Manfra et N. P. Armitage. « Measurements of cyclotron resonance of the interfacial states in strong spin–orbit coupled 2D electron gases proximitized with aluminum ». Applied Physics Letters 120, n^o 14 (4 avril 2022) : 142105. http://dx.doi.org/10.1063/5.0087401.

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Two dimensional electron gases (2DEGs) in InAs quantum wells proximitized by aluminum are promising platforms for topological qubits based on Majorana zero modes. However, there are still substantial uncertainties associated with the nature of electronic states at the interface of these systems. It is challenging to probe the properties of these hybridized states as they are buried under a relatively thick aluminum layer. In this work, we have investigated a range of InAs/In1−xGaxAs heterostructures with Al overlayers using high precision time-domain THz spectroscopy (TDTS). Despite the thick metallic overlayer, we observe a prominent cyclotron resonance in a magnetic field that can be associated with the response of the interfacial states. Measurements of the THz range complex Faraday rotation allow the extraction of the sign and magnitude of the effective mass, density of charge carriers, and scattering times of the 2DEG despite the close proximity of the aluminum layer. We discuss the extracted band parameters and connect their values to the known physics of these materials.

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Sartori, C., et W. Preetz. « Die Schwingungsfeinstruktur der Elektronenspektren des 13C- und 18O-markierten trans-Dioxotetracyanoosmats (VI),[OsO2(CN)4]2 - ». Zeitschrift für Naturforschung A 43, n^o 3 (1 mars 1988) : 239–47. http://dx.doi.org/10.1515/zna-1988-0310.

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The electronic absorption spectrum of the solid tetramethyl-ammonium salt of [OsO2(CN)4]2 - is measured at 10 K. The five distinct band systems exhibit vibrational progressions in the range 660-750 cm - 1, corresponding to the Os = O stretching vibrations sometimes coupled with ν(OsC). From this vibrational fine structure the electronic origin is deduced and verified by characteristic isotopic shifts by 18O and 13C. The two bands at lowest energy are assigned to the d-d-transitions 1A1g [b22g] → 3Eg [b12g e1g] (620 - 460 nm) and 1A1g [b22g] → 1Eg [b12g e1g] (490 - 400 nm). The 3Eg state is split by spin-orbit coupling into 5 components, from the one at lowest energy a luminescence emission (830 - 670 nm) takes place with a progression of 860 cm-1, corresponding to the symmetric Os = O stretching vibration in the electronic ground state. The more intense bands are assigned to charge transfer transitions from oxo π-orbitals into unoccupied niveaus of Os (VI): 1A1g [e4u] → 3A2u [e3u e1g] (390 - 340); → 1A1u [e3u e1g] (340 - 290) and → 1Eu [e3u b11g (290 - 230 nm). The singlet-triplet distances are 3200-3600 cm - 1. From a Franck-Condon analysis an excited state elongation of 10-13 pm for the osmyl groups is calculated.

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BURKE, KIERON, et JOHN P. PERDEW. « DENSITY FUNCTIONALS AND SMALL INTERPARTICLE SEPARATIONS IN ELECTRONIC SYSTEMS ». Modern Physics Letters B 09, n^o 14 (20 juin 1995) : 829–38. http://dx.doi.org/10.1142/s0217984995000784.

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We review some recent results concerning the probability that two electrons will be found close together in any interacting electronic system, and why this probability is usually well approximated by local (LSD) and semilocal spin density functional theories. The success of these approximations for the energy in "normal" systems is explained by the usual sum rule arguments on the system- and spherically-averaged exchange-correlation hole density <n xc (u)>, coupled with the nearly correct, but not exact, behavior of these approximations as the interelectronic separation u → 0. We argue that the accuracy of the LSD on-top hole density in "normal" systems is due to its accuracy in the noninteracting, weakly-interacting, and strongly-interacting limits.

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Das, Tushar K., et Michael G. Cottam. « Coupled Dipolar Spin Waves of Magnetic Multilayer Systems With Cylindrical Geometries ». IEEE Transactions on Magnetics 46, n^o 6 (juin 2010) : 1544–47. http://dx.doi.org/10.1109/tmag.2010.2042929.

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Nizovtsev, Alexander P., Aliaksandr L. Pushkarchuk, Sergei Ya Kilin, Nikolai I. Kargin, Alexander S. Gusev, Marina O. Smirnova et Fedor Jelezko. « Hyperfine Interactions in the NV-13C Quantum Registers in Diamond Grown from the Azaadamantane Seed ». Nanomaterials 11, n^o 5 (14 mai 2021) : 1303. http://dx.doi.org/10.3390/nano11051303.

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Nanostructured diamonds hosting optically active paramagnetic color centers (NV, SiV, GeV, etc.) and hyperfine-coupled with them quantum memory 13C nuclear spins situated in diamond lattice are currently of great interest to implement emerging quantum technologies (quantum information processing, quantum sensing and metrology). Current methods of creation such as electronic-nuclear spin systems are inherently probabilistic with respect to mutual location of color center electronic spin and 13C nuclear spins. A new bottom-up approach to fabricate such systems is to synthesize first chemically appropriate diamond-like organic molecules containing desired isotopic constituents in definite positions and then use them as a seed for diamond growth to produce macroscopic diamonds, subsequently creating vacancy-related color centers in them. In particular, diamonds incorporating coupled NV-13C spin systems (quantum registers) with specific mutual arrangements of NV and 13C can be obtained from anisotopic azaadamantane molecule. Here we predict the characteristics of hyperfine interactions (hfi) for the NV-13C systems in diamonds grown from various isotopically substituted azaadamantane molecules differing in 13C position in the seed, as well as the orientation of the NV center in the post-obtained diamond. We used the spatial and hfi data simulated earlier for the H-terminated cluster C510[NV]-H252. The data obtained can be used to identify (and correlate with the seed used) the specific NV-13C spin system by measuring, e.g., the hfi-induced splitting of the mS = ±1 sublevels of the NV center in optically detected magnetic resonance (ODMR) spectra being characteristic for various NV-13C systems.

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Perdriat, Maxime, Clément Pellet-Mary, Paul Huillery, Loïc Rondin et Gabriel Hétet. « Spin-Mechanics with Nitrogen-Vacancy Centers and Trapped Particles ». Micromachines 12, n^o 6 (1 juin 2021) : 651. http://dx.doi.org/10.3390/mi12060651.

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Controlling the motion of macroscopic oscillators in the quantum regime has been the subject of intense research in recent decades. In this direction, opto-mechanical systems, where the motion of micro-objects is strongly coupled with laser light radiation pressure, have had tremendous success. In particular, the motion of levitating objects can be manipulated at the quantum level thanks to their very high isolation from the environment under ultra-low vacuum conditions. To enter the quantum regime, schemes using single long-lived atomic spins, such as the electronic spin of nitrogen-vacancy (NV) centers in diamond, coupled with levitating mechanical oscillators have been proposed. At the single spin level, they offer the formidable prospect of transferring the spins’ inherent quantum nature to the oscillators, with foreseeable far-reaching implications in quantum sensing and tests of quantum mechanics. Adding the spin degrees of freedom to the experimentalists’ toolbox would enable access to a very rich playground at the crossroads between condensed matter and atomic physics. We review recent experimental work in the field of spin-mechanics that employ the interaction between trapped particles and electronic spins in the solid state and discuss the challenges ahead. Our focus is on the theoretical background close to the current experiments, as well as on the experimental limits, that, once overcome, will enable these systems to unleash their full potential.

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Harris, Andrew T., Christopher D. Petersen et Hanspeter Schaub. « Linear Coupled Attitude–Orbit Control Through Aerodynamic Drag ». Journal of Guidance, Control, and Dynamics 43, n^o 1 (janvier 2020) : 122–31. http://dx.doi.org/10.2514/1.g004521.

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Booth, D., S. T. Rittenhouse, J. Yang, H. R. Sadeghpour et J. P. Shaffer. « Production of trilobite Rydberg molecule dimers with kilo-Debye permanent electric dipole moments ». Science 348, n^o 6230 (2 avril 2015) : 99–102. http://dx.doi.org/10.1126/science.1260722.

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Permanent electric dipole moments are important for understanding symmetry breaking in molecular physics, control of chemical reactions, and realization of strongly correlated many-body quantum systems. However, large molecular permanent electric dipole moments are challenging to realize experimentally. We report the observation of ultralong-range Rydberg molecules with bond lengths of ~100 nanometers and kilo-Debye permanent electric dipole moments that form when an ultracold ground-state cesium (Cs) atom becomes bound within the electronic cloud of an extended Cs electronic orbit. The electronic character of this hybrid class of “trilobite” molecules is dominated by degenerate Rydberg manifolds, making them difficult to produce by conventional photoassociation. We used detailed coupled-channel calculations to reproduce their properties quantitatively. Our findings may lead to progress in ultracold chemistry and strongly correlated many-body physics.

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Evans, R. E., M. K. Bhaskar, D. D. Sukachev, C. T. Nguyen, A. Sipahigil, M. J. Burek, B. Machielse et al. « Photon-mediated interactions between quantum emitters in a diamond nanocavity ». Science 362, n^o 6415 (20 septembre 2018) : 662–65. http://dx.doi.org/10.1126/science.aau4691.

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Photon-mediated interactions between quantum systems are essential for realizing quantum networks and scalable quantum information processing. We demonstrate such interactions between pairs of silicon-vacancy (SiV) color centers coupled to a diamond nanophotonic cavity. When the optical transitions of the two color centers are tuned into resonance, the coupling to the common cavity mode results in a coherent interaction between them, leading to spectrally resolved superradiant and subradiant states. We use the electronic spin degrees of freedom of the SiV centers to control these optically mediated interactions. Such controlled interactions will be crucial in developing cavity-mediated quantum gates between spin qubits and for realizing scalable quantum network nodes.

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Sheong, FuKit, Jing-Xuan Zhang et Zhenyang Lin. « Revitalizing Spin Natural Orbital Analysis : Electronic Structures of Mixed-Valence Compounds, Singlet Biradicals, and Antiferromagnetically Coupled Systems ». Journal of Computational Chemistry 40, n^o 10 (16 janvier 2019) : 1172–84. http://dx.doi.org/10.1002/jcc.25762.

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Pouget, Jean-Paul. « Spin-Peierls, Spin-Ladder and Kondo Coupling in Weakly Localized Quasi-1D Molecular Systems : An Overview ». Magnetochemistry 9, n^o 2 (13 février 2023) : 57. http://dx.doi.org/10.3390/magnetochemistry9020057.

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We review the magneto-structural properties of electron–electron correlated quasi-one- dimensional (1D) molecular organics. These weakly localized quarter-filled metallic-like systems with pronounced spin 1/2 antiferromagnetic (AF) interactions in stack direction exhibit a spin charge decoupling where magnetoelastic coupling picks up spin 1/2 to pair into S = 0 singlet dimers. This is well illustrated by the observation of a spin-Peierls (SP) instability in the (TMTTF)2X Fabre salts and related salts with the o-DMTTF donor. These instabilities are revealed by the formation of a pseudo-gap in the spin degrees of freedom triggered by the development of SP structural correlations. The divergence of these 1D fluctuations, together with the interchain coupling, drive a 3D-SP ground state. More surprisingly, we show that the Per2-M(mnt)2 system, undergoing a Kondo coupling between the metallic Per stack and the dithiolate stack of localized AF coupled spin ½ (for M = Pd, Ni, Pt), enhances the SP instability. Then, we consider the zig-zag spin ladder DTTTF2-M(mnt)2 system, where unusual singlet ground state properties are due to a combination of a 4kF charge localization effect in stack direction and a 2kF SP instability along the zig-zag ladder. Finally, we consider some specific features of correlated 1D systems concerning the coexistence of symmetrically different 4kF BOW and 4kF CDW orders in quarter-filled organics, and the nucleation of solitons in perturbed SP systems.

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Yao, Peter, et Timothy Sands. « Micro Satellite Orbital Boost by Electrodynamic Tethers ». Micromachines 12, n^o 8 (31 juillet 2021) : 916. http://dx.doi.org/10.3390/mi12080916.

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In this manuscript, a method for maneuvering a spacecraft using electrically charged tethers is explored. The spacecraft’s velocity vector can be modified by interacting with Earth’s magnetic field. Through this method, a spacecraft can maintain an orbit indefinitely by reboosting without the constraint of limited propellant. The spacecraft-tether system dynamics in low Earth orbit are simulated to evaluate the effects of Lorentz force and torques on translational motion. With 500-meter tethers charged with a 1-amp current, a 100-kg spacecraft can gain 250 m of altitude in one orbit. By evaluating the combined effects of Lorenz force and the coupled effects of Lorentz torque propagation through Euler’s moment equation and Newton’s translational motion equations, the simulated spacecraft-tether system can orbit indefinitely at altitudes as low as 275 km. Through a rare evaluation of the nonlinear coupling of the six differential equations of motion, the one finding is that an electrodynamic tether can be used to maintain a spacecraft’s orbit height indefinitely for very low Earth orbits. However, the reboost maneuver is inefficient for high inclination orbits and has high electrical power requirement. To overcome greater aerodynamic drag at lower altitudes, longer tethers with higher power draw are required.

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Zhang, Yinghui, Chen Ma, Songjing Ma, Junfeng Pan, Xiaohong Sui, Boxuan Lin et Mengjie Shi. « Rigid–Flexible Coupled System Attitude–Orbit Integration Fixed-Time Control ». Electronics 12, n^o 15 (3 août 2023) : 3329. http://dx.doi.org/10.3390/electronics12153329.

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A diffractive imaging system consisting of two satellites is analyzed in view of dynamics. The mathematical model of rigid and flexion couples is studied to describe the relative motion of diffractive satellites and imaging satellites. Based on an integrated dynamics model with dual quaternion, a fixed-time non-singular terminal sliding mode controller is designed to meet the requirements of Earth observation. Finally, introducing the non-singular terminal sliding mode as the control group, a comparative simulation of relative motion and control is implemented to verify the controller and dynamics model.

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Khaneja, Navin. « Time optimal control of coupled spin dynamics : A global analysis ». Automatica 111 (janvier 2020) : 108639. http://dx.doi.org/10.1016/j.automatica.2019.108639.

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Benetis, Nikolas P. « Spin-lattice relaxation of ligand nuclei in slowly reorienting paramagnetic complexes in the electronic doublet spin state (). A theoretical approach for strongly coupled two-spin systems ». Journal of Magnetic Resonance (1969) 68, n^o 3 (juillet 1986) : 469–89. http://dx.doi.org/10.1016/0022-2364(86)90337-9.

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Tsukerblat, Boris, Andrew Palii et Juan Modesto Clemente-Juan. « Self-trapping of charge polarized states in four-dot molecular quantum cellular automata : bi-electronic tetrameric mixed-valence species ». Pure and Applied Chemistry 87, n^o 3 (1 mars 2015) : 271–82. http://dx.doi.org/10.1515/pac-2014-0904.

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AbstractOur interest in this article is prompted by the problem of the vibronic self-trapping of charge polarized states in the four-dot molecular quantum cellular automata (mQCA), a paradigm for nanoelectronics, in which binary information is encoded in charge configuration of the mQCA cell. We report the evaluation of the electronic states and the adiabatic potentials of mixed-valence (MV) systems in which two electrons (or holes) are shared among four sites. These systems are exemplified by the two kinds of tetra–ruthenium (2Ru(II)+ 2Ru(III)) clusters (assembled as two coupled Creutz–Taube dimers) for which molecular implementation of mQCA was proposed. The tetra–ruthenium clusters include two holes shared among four sites and correspondingly we employ the model which takes into account the electron transfer processes as well as the Coulomb repulsion in the different instant positions of localization. The vibronic self-trapping is considered within the conventional vibronic Piepho, Krausz and Schatz (PKS) model adapted to the bi-electronic MV species with the square topology. This leads to a complicated vibronic problems (21A1g + 1B1g + 1B2g + 1Eu) ⊗ (b1g + eu) and (3A2g + 3B1g + 23Eu) ⊗ (b1g + eu) for spin-singlet and spin-triplet states correspondingly. The adiabatic potentials are evaluated with account for the low lying Coulomb levels in which the antipodal sites are occupied, the case just actual for utilization in mQCA. The conditions for the vibronic localization in spin-singlet and spin-triplet states are revealed in terms of the two actual transfer pathways parameters and strength of the vibronic coupling.

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WAN, F., M. B. A. JALIL, S. G. TAN et T. FUJITA. « SPIN-POLARIZED TRANSPORT THROUGH GaAs/AlGaAs PARABOLIC QUANTUM WELL UNDER A UNIFORM MAGNETIC FIELD ». International Journal of Nanoscience 08, n^o 01n02 (février 2009) : 71–74. http://dx.doi.org/10.1142/s0219581x09005736.

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We present a GaAs / AlGaAs -based quantum well device capable of achieving an appreciable spin polarization coupled with high electron transmission. Our numerical results indicate that the device is able to achieve a high spin polarization without the need for less commonly used materials with high g-factors required by previously proposed semiconductor-based systems. The electron transmission and spin polarization amplitude of our structure is found to be robust to the length of the parabolic well, which could ease the fabrication of such structures in practical applications.

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McInnes, Colin R. « Low-Thrust Orbit Raising with Coupled Plane Change and J Precession ». Journal of Guidance, Control, and Dynamics 20, n^o 3 (mai 1997) : 607–9. http://dx.doi.org/10.2514/2.4084.

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Li, Quan, Chao Wu, Yu Xie, Song Li, Hongqiang Li et Lijun Jin. « Full Complex-Amplitude Modulation of Surface Waves Based on Spin-Decoupled Metasurface ». Micromachines 14, n^o 8 (27 juillet 2023) : 1511. http://dx.doi.org/10.3390/mi14081511.

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This work proposes a method for surface wave (SW) coupling along with flexible complex amplitude modulation of its wavefront. The linearly polarized incident plane wave is coupled into the surface mode with complex wavefront by exploiting the spin-decouple nature of a reflective chiral meta-atom. As verification, two kinds of metasurface couplers are designed. The first kind contains two examples for SW airy beam generation with and without deflection under linearly polarized illumination, respectively. The second kind is a bi-functional device capable of SW focusing under left-handed circularly polarized illumination, and propagating wave deflection under right-handed circularly polarized illumination, respectively, to verify the fundamental spin-decoupled character. Simulated and experimental results are in good agreement. We believe that this method provides a flexible approach for complex SW applications in integrated optics, optical sensing, and other related fields.

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Valentí, R., T. Saha-Dasgupta, H. O. Jeschke, B. Rahaman, H. Rosner, P. Lemmens, R. Takagi et M. Johnsson. « Comparative investigation of the coupled-tetrahedra quantum spin systems Cu2Te2O5X2, X=Cl, Br and Cu4Te5O12Cl4 ». Physica C : Superconductivity and its Applications 460-462 (septembre 2007) : 462–63. http://dx.doi.org/10.1016/j.physc.2007.03.255.

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Hill, Charles D., Eldad Peretz, Samuel J. Hile, Matthew G. House, Martin Fuechsle, Sven Rogge, Michelle Y. Simmons et Lloyd C. L. Hollenberg. « A surface code quantum computer in silicon ». Science Advances 1, n^o 9 (octobre 2015) : e1500707. http://dx.doi.org/10.1126/sciadv.1500707.

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The exceptionally long quantum coherence times of phosphorus donor nuclear spin qubits in silicon, coupled with the proven scalability of silicon-based nano-electronics, make them attractive candidates for large-scale quantum computing. However, the high threshold of topological quantum error correction can only be captured in a two-dimensional array of qubits operating synchronously and in parallel—posing formidable fabrication and control challenges. We present an architecture that addresses these problems through a novel shared-control paradigm that is particularly suited to the natural uniformity of the phosphorus donor nuclear spin qubit states and electronic confinement. The architecture comprises a two-dimensional lattice of donor qubits sandwiched between two vertically separated control layers forming a mutually perpendicular crisscross gate array. Shared-control lines facilitate loading/unloading of single electrons to specific donors, thereby activating multiple qubits in parallel across the array on which the required operations for surface code quantum error correction are carried out by global spin control. The complexities of independent qubit control, wave function engineering, and ad hoc quantum interconnects are explicitly avoided. With many of the basic elements of fabrication and control based on demonstrated techniques and with simulated quantum operation below the surface code error threshold, the architecture represents a new pathway for large-scale quantum information processing in silicon and potentially in other qubit systems where uniformity can be exploited.

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Huang, Xu, Zheng You, Liangliang Chen et Jinlong Yu. « Coupled Relative Orbit and Attitude Control Augmented by the Geomagnetic Lorentz Propulsions ». Journal of Guidance, Control, and Dynamics 44, n^o 6 (juin 2021) : 1143–56. http://dx.doi.org/10.2514/1.g005212.

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Munekata, H. « Optical manipulation of coupled spins in magnetic semiconductor systems : A path toward spin optoelectronics ». Physica E : Low-dimensional Systems and Nanostructures 29, n^o 3-4 (novembre 2005) : 475–82. http://dx.doi.org/10.1016/j.physe.2005.06.010.

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Shen, Xiang, Liye Zhao et Fei Ge. « Structural Optimization and MEMS Implementation of the NV Center Phonon Piezoelectric Device ». Micromachines 13, n^o 10 (28 septembre 2022) : 1628. http://dx.doi.org/10.3390/mi13101628.

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The nitrogen-vacancy (NV) center of the diamond has attracted widespread attention because of its high sensitivity in quantum precision measurement. The phonon piezoelectric device of the NV center is designed on the basis of the phonon-coupled regulation mechanism. The propagation characteristics and acoustic wave excitation modes of the phonon piezoelectric device are analyzed. In order to improve the performance of phonon-coupled manipulation, the influence of the structural parameters of the diamond substrate and the ZnO piezoelectric layer on the phonon propagation characteristics are analyzed. The structure of the phonon piezoelectric device of the NV center is optimized, and its Micro-Electro-Mechanical System (MEMS) implementation and characterization are carried out. Research results show that the phonon resonance manipulation method can effectively increase the NV center’s spin transition probability using the MEMS phonon piezoelectric device prepared in this paper, improving the quantum spin manipulation efficiency.

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D'Alessandro, D. « Controllability, observability, and parameter identification of two coupled spin 1's ». IEEE Transactions on Automatic Control 50, n^o 7 (juillet 2005) : 1054–58. http://dx.doi.org/10.1109/tac.2005.851460.

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Moxim, S. J., J. P. Ashton, M. A. Anders et J. T. Ryan. « Combining electrically detected magnetic resonance techniques to study atomic-scale defects generated by hot-carrier stressing in HfO₂/SiO₂/Si transistors ». Journal of Applied Physics 133, n^o 14 (14 avril 2023) : 145702. http://dx.doi.org/10.1063/5.0145937.

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This work explores the atomic-scale nature of defects within hafnium dioxide/silicon dioxide/silicon (HfO2/SiO2/Si) transistors generated by hot-carrier stressing. The defects are studied via electrically detected magnetic resonance (EDMR) through both spin-dependent charge pumping and spin-dependent tunneling. When combined, these techniques probe defects both at the Si-side interface and within the oxide-based gate stack. The defects at the Si-side interface are found to strongly resemble Pb-like defects common in the Si/SiO2 system. The defect within the gate stack has not been positively identified in the literature thus far; this work argues that it is a Si-dangling bond coupled to one or more hafnium atoms. The use of EDMR techniques indicates that the defects detected here are relevant to electronic transport and, thus, device reliability. This work also highlights the impressive analytical power of combined EDMR techniques when studying complex, modern materials systems.

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Römer, Anton, Lukas Hasecke, Peter Blöchl et Ricardo A. Mata. « A Review of Density Functional Models for the Description of Fe(II) Spin-Crossover Complexes ». Molecules 25, n^o 21 (6 novembre 2020) : 5176. http://dx.doi.org/10.3390/molecules25215176.

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Spin-crossover (SCO) materials have for more than 30 years stood out for their vast application potential in memory, sensing and display devices. To reach magnetic multistability conditions, the high-spin (HS) and low-spin (LS) states have to be carefully balanced by ligand field stabilization and spin-pairing energies. Both effects could be effectively modelled by electronic structure theory, if the description would be accurate enough to describe these concurrent influences to within a few kJ/mol. Such a milestone would allow for the in silico-driven development of SCO complexes. However, so far, the ab initio simulation of such systems has been dominated by general gradient approximation density functional calculations. The latter can only provide the right answer for the wrong reasons, given that the LS states are grossly over-stabilized. In this contribution, we explore different venues for the parameterization of hybrid functionals. A fitting set is provided on the basis of explicitly correlated coupled cluster calculations, with single- and multi-dimensional fitting approaches being tested to selected classes of hybrid functionals (hybrid, range-separated, and local hybrid). Promising agreement to benchmark data is found for a rescaled PBE0 hybrid functional and a local version thereof, with a discussion of different atomic exchange factors.

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Minnegaliev, M. M., R. V. Urmancheev, V. A. Skrebnev et S. A. Moiseev. « Investigation of a Sequence of Dynamical Decoupling Pulses for Dipole-Coupled Spin Systems with Inhomogeneous Broadening ». Optics and Spectroscopy 126, n^o 1 (janvier 2019) : 1–5. http://dx.doi.org/10.1134/s0030400x19010120.

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Pushkarchuk, A. L., S. A. Kuten, V. A. Pushkarchuk, A. P. Nizovtsev et S. Ya Kilin. « Neutral Silicon-Vacancy Color Center in Diamond : Cluster Simulation of Spatial and Hyperfine Characteristics ». International Journal of Nanoscience 18, n^o 03n04 (26 mars 2019) : 1940010. http://dx.doi.org/10.1142/s0219581x19400106.

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One of the most promising platforms to implement quantum technologies are coupled electron-nuclear spins in solids in which electrons can play a role of “fast” qubits, while nuclear spins can store quantum information for a very long time due to their exceptionally high isolation from the environment. The well-known representative of such systems is the “nitrogen-vacancy” (NV) center in diamond coupled by a hyperfine interaction to its intrinsic [Formula: see text]N/[Formula: see text]N nuclear spin or to [Formula: see text]C nuclear spins presenting in the diamond lattice. More recently, other paramagnetic color centers in diamond have been identified exhibiting even better characteristics in comparison to the NV center. Essential prerequisite for a high-fidelity spin manipulation in these systems with tailored control pulse sequences is a complete knowledge of hyperfine interactions. Development of this understanding for one of the new color centers in diamond, viz., neutral “silicon-vacancy” (SiV0) color center, is a primary goal of this paper, in which we are presenting preliminary results of computer simulation of spatial and hyperfine characteristics of SiV0 center in H-terminated clusters C[Formula: see text][SiV0]H[Formula: see text] and C[Formula: see text][SiV0]H[Formula: see text].

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Kikuchi, Shota, Yuichi Tsuda, Makoto Yoshikawa et Jun’ichiro Kawaguchi. « Stability Analysis of Coupled Orbit–Attitude Dynamics Around Asteroids Using Finite-Time Lyapunov Exponents ». Journal of Guidance, Control, and Dynamics 42, n^o 6 (juin 2019) : 1289–305. http://dx.doi.org/10.2514/1.g003879.

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Barrère, Caroline, Pierre Thureau, André Thévand et Stéphane Viel. « A convenient method for the measurements of transverse relaxation rates in homonuclear scalar coupled spin systems ». Chemical Communications 47, n^o 32 (2011) : 9209. http://dx.doi.org/10.1039/c1cc13042k.

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Martelli, Valentina, Ang Cai, Emilian M. Nica, Mathieu Taupin, Andrey Prokofiev, Chia-Chuan Liu, Hsin-Hua Lai et al. « Sequential localization of a complex electron fluid ». Proceedings of the National Academy of Sciences 116, n^o 36 (20 août 2019) : 17701–6. http://dx.doi.org/10.1073/pnas.1908101116.

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Complex and correlated quantum systems with promise for new functionality often involve entwined electronic degrees of freedom. In such materials, highly unusual properties emerge and could be the result of electron localization. Here, a cubic heavy fermion metal governed by spins and orbitals is chosen as a model system for this physics. Its properties are found to originate from surprisingly simple low-energy behavior, with 2 distinct localization transitions driven by a single degree of freedom at a time. This result is unexpected, but we are able to understand it by advancing the notion of sequential destruction of an SU(4) spin–orbital-coupled Kondo entanglement. Our results implicate electron localization as a unified framework for strongly correlated materials and suggest ways to exploit multiple degrees of freedom for quantum engineering.

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Schmool, David S., Daniel Markó, Ko-Wei Lin, Aurelio Hierro-Rodríguez, Carlos Quirós, Javier Díaz, Luis Manuel Álvarez-Prado et Jong-Ching Wu. « Ferromagnetic Resonance Studies in Magnetic Nanosystems ». Magnetochemistry 7, n^o 9 (12 septembre 2021) : 126. http://dx.doi.org/10.3390/magnetochemistry7090126.

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Ferromagnetic resonance is a powerful method for the study of all classes of magnetic materials. The experimental technique has been used for many decades and is based on the excitation of a magnetic spin system via a microwave (or rf) field. While earlier methods were based on the use of a microwave spectrometer, more recent developments have seen the widespread use of the vector network analyzer (VNA), which provides a more versatile measurement system at almost comparable sensitivity. While the former is based on a fixed frequency of excitation, the VNA enables frequency-dependent measurements, allowing more in-depth analysis. We have applied this technique to the study of nanostructured thin films or nanodots and coupled magnetic layer systems comprised of exchange-coupled ferromagnetic layers with in-plane and perpendicular magnetic anisotropies. In the first system, we have investigated the magnetization dynamics in Co/Ag bilayers and nanodots. In the second system, we have studied Permalloy (Ni80Fe20, hereafter Py) thin films coupled via an intervening Al layer of varying thickness to a NdCo film which has perpendicular magnetic anisotropy.

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Albani, Guglielmo, Alberto Calloni, Andrea Picone, Alberto Brambilla, Michele Capra, Alessandro Lodesani, Lamberto Duò, Marco Finazzi, Franco Ciccacci et Gianlorenzo Bussetti. « An In-Depth Assessment of the Electronic and Magnetic Properties of a Highly Ordered Hybrid Interface : The Case of Nickel Tetra-Phenyl-Porphyrins on Fe(001)–p(1 × 1)O ». Micromachines 12, n^o 2 (13 février 2021) : 191. http://dx.doi.org/10.3390/mi12020191.

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In this paper we focus on the structural, electronic, and magnetic properties of Ni tetra-phenyl-porphyrins (NiTPP) grown on top of Fe(001)–p(1 × 1)O. Ordered thin films of metal TPP molecules are potentially interesting for organic electronic and spintronic applications, especially when they are coupled to a ferromagnetic substrate. Unfortunately, porphyrin layers deposited on top of ferromagnetic substrates do not generally show long-range order. In this work, we provide evidence of an ordered disposition of the organic film above the iron surface and we prove that the thin layer of iron oxide decouples the molecules from the substrate, thus preserving the molecular electronic features, especially the HOMO-LUMO gap, even when just a few organic layers are deposited. The effect of the exposure to molecular oxygen is also investigated and an increased robustness against oxidation with respect to the bare substrate is detected. Finally, we present our results for the magnetic analysis performed by spin resolved spectroscopy, finding a null magnetic coupling between the molecules and the substrate.

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Bogdanov, Nikolay A., Giovanni Li Manni, Sandeep Sharma, Olle Gunnarsson et Ali Alavi. « Enhancement of superexchange due to synergetic breathing and hopping in corner-sharing cuprates ». Nature Physics 18, n^o 2 (20 décembre 2021) : 190–95. http://dx.doi.org/10.1038/s41567-021-01439-1.

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AbstractCuprates with corner-sharing CuO4 plaquettes have received much attention owing to the discoveries of high-temperature superconductivity and exotic states where spin and charge or spin and orbital degrees of freedom are separated. In these systems spins are strongly coupled antiferromagnetically via superexchange mechanisms, with high nearest-neighbour coupling varying among different compounds. The electronic properties of cuprates are also known to be highly sensitive to the presence, distance and displacement of apical oxygens perpendicular to the CuO2 planes. Here we present ab initio quantum chemistry calculations of the nearest-neighbour superexchange antiferromagnetic (AF) coupling J of two cuprates, Sr2CuO3 and La2CuO4. The former lacks apical oxygens, whilst the latter contain two apical oxygens per CuO2 unit completing a distorted octahedral environment around each Cu atom. Good agreement is obtained with experimental estimates for both systems. Analysis of the correlated wavefunctions together with extended superexchange models shows that there is an important synergetic effect of the Coulomb interaction and the O–Cu hopping, namely a correlated breathing-enhanced hopping mechanism. This is a new ingredient in superexchange models. Suppression of this mechanism leads to drastic reduction in the AF coupling, indicating that it is of primary importance in generating the strong interactions. We also find that J increases substantially as the distance between Cu and apical O is increased.

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Jiang, Xiao, Yiyuan Xie, Bocheng Liu, Yichen Ye, Tingting Song, Junxiong Chai et Qianfeng Tang. « Dynamics of mutually coupled quantum dot spin-VCSELs subject to key parameters ». Nonlinear Dynamics 105, n^o 4 (25 août 2021) : 3659–71. http://dx.doi.org/10.1007/s11071-021-06760-1.

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RÖHLSBERGER, RALF. « MAGNETISM AND LATTICE DYNAMICS OF NANOSCALE STRUCTURES STUDIED BY NUCLEAR RESONANT SCATTERING OF SYNCHROTRON RADIATION ». International Journal of Nanoscience 04, n^o 05n06 (octobre 2005) : 975–86. http://dx.doi.org/10.1142/s0219581x05003942.

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Nuclear resonant scattering of synchrotron radiation is applied to investigate the magnetic structure and the lattice dynamics of nanoscale systems. The outstanding brilliance of modern synchrotron radiation sources allows for sensitivities to smallest amounts of material. Due to the isotopic sensitivity of the scattering process, ultrathin probe layers of Mössbauer isotopes can be used to map out the magnetic and vibrational structure of thin films with sub-nm spatial resolution. Elastic nuclear resonant scattering is applied to determine the magnetic spin structure of an exchange-coupled bilayer system. Inelastic nuclear resonant scattering was used to determine the vibrational density of states in Fe islands on the W(110) surface.

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Zwier, Olger V., Tom Bosma, Carmem M. Gilardoni, Xu Yang, Alexander R. Onur, Takeshi Ohshima, Nguyen T. Son et Caspar H. van der Wal. « Electromagnetically induced transparency in inhomogeneously broadened divacancy defect ensembles in SiC ». Journal of Applied Physics 131, n^o 9 (7 mars 2022) : 094401. http://dx.doi.org/10.1063/5.0077112.

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Electromagnetically induced transparency (EIT) is a phenomenon that can provide strong and robust interfacing between optical signals and quantum coherence of electronic spins. In its archetypical form, mainly explored with atomic media, it uses a (near-)homogeneous ensemble of three-level systems, in which two low-energy spin-1/2 levels are coupled to a common optically excited state. We investigate the implementation of EIT with c-axis divacancy color centers in silicon carbide. While this material has attractive properties for quantum device technologies with near-IR optics, implementing EIT is complicated by the inhomogeneous broadening of the optical transitions throughout the ensemble and the presence of multiple ground-state levels. These may lead to darkening of the ensemble upon resonant optical excitation. Here, we show that EIT can be established with high visibility also in this material platform upon careful design of the measurement geometry. Comparison of our experimental results with a model based on the Lindblad equations indicates that we can create coherences between different sets of two levels all-optically in these systems, with potential impact for RF-free quantum sensing applications. Our work provides an understanding of EIT in multi-level systems with significant inhomogeneities, and our considerations are valid for a wide array of defects in semiconductors.

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Chen, Hao, So Young Jeon et Sara A. Majetich. « Magnetostatic coupling effects on reversal dynamics ». Journal of Physics D : Applied Physics 55, n^o 26 (8 avril 2022) : 265002. http://dx.doi.org/10.1088/1361-6463/ac62a1.

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Abstract The effects of magnetostatic coupling on switching dynamics are investigated for assemblies of patterned disc-shaped magnetic elements using mumax3 micromagnetic simulations. The arrangements of coupled dots were designed using information about the switching fields and reversal dynamics of isolated dots, as well as the magnitude of the magnetic stray fields they generate. The magnetization dynamics for individual dots was examined during a reversal cascade down a linear chain of dots. The magnetization angle fluctuated much more when neighboring dots have opposite magnetization directions, consistent with a lower energy barrier for reversal. The data were analyzed to differentiate thermal and interaction field effects. While many systems of interacting nanomagnets have been analyzed in terms of empirical models, the dynamical energy barrier approach offers a methodology with a more detailed and physically intuitive way to study both simple systems like the chain and more complex assemblies such as artificial spin ice.

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Yang, Huiyuan, Yongshun Zhang, Zhenhu Liu, Xu Liu et Guanxi Liu. « Posture Dynamic Modeling and Stability Analysis of a Magnetic Driven Dual-Spin Spherical Capsule Robot ». Micromachines 12, n^o 3 (26 février 2021) : 238. http://dx.doi.org/10.3390/mi12030238.

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In order to realize the intervention operation in the unstructured and ample environments such as stomach and colon, a dual-spin spherical capsule robot (DSCR) driven by pure magnetic torque generated by the universal rotating magnetic field (URMF) is proposed. The coupled magnetic torque, the viscoelastic friction torque, and the gravity torque were analyzed. Furthermore, the posture dynamic model describing the electric-magnetic-mechanical-liquid coupling dynamic behavior of the DSCR in the gastrointestinal (GI) tract was established. This model is a second-order periodic variable coefficient dynamics equation, which should be regarded as an extension of the Lagrange case for the dual-spin body system under the fixed-point motion, since the external torques were applied. Based on the Floquet–Lyapunov theory, the stability domain of the DSCR for the asymptotically stable motion and periodic motion were obtained by investigating the influence of the angular velocity of the URMF, the magnetic induction intensity, and the centroid deviation. Research results show that the DSCR can realize three kinds of motion, which are asymptotically stable motion, periodic motion, and chaotic motion, according to the distribution of the system characteristic multipliers. Moreover, the posture stability of the DSCR can be improved by increasing the angular velocity of the URMF and reducing the magnetic induction intensity.

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