Dissertations / Theses on the topic 'Surface phase transition'
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Park, Hyunhang. "Spin Systems far from Equilibrium: Aging and Dynamic Phase Transition." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/19323.
Full textPh. D.
Maeda, Nobuo, and nobuo@engineering ucsb edu. "Phase Transitions of Long-Chain N-Alkanes at Interfaces." The Australian National University. Research School of Physical Sciences and Engineering, 2001. http://thesis.anu.edu.au./public/adt-ANU20011203.151921.
Full textCunha, Frederico. "A surface charge induced order-disorder phase transition in organic monolayers." FIU Digital Commons, 1995. http://digitalcommons.fiu.edu/etd/2690.
Full textKoyama, Akira. "Acceleration of Electrochemical Reactions in Confined Nanospaces Caused by Surface-Induced Phase Transition." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225589.
Full textHopkinson, Andrew. "A molecular beam study of the CO-induced surface phase transition on Pt{100}." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308382.
Full textSoleiman, Samira. "Contribution à l'étude de la transition de phase des greffes denses de longues chaînes grasses à la surface des silices." Lyon 1, 1993. http://www.theses.fr/1993LYO10133.
Full textHorstmann, Jan Gerrit [Verfasser]. "Ultrafast Probing and Coherent Vibrational Control of a Surface Structural Phase Transition / Jan Gerrit Horstmann." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://nbn-resolving.de/urn:nbn:de:gbv:7-21.11130/00-1735-0000-0008-58F2-4-3.
Full textPatra, Abhirup. "Surface properties, adsorption, and phase transitions with a dispersion-corrected density functional." Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/516784.
Full textPh.D.
Understanding the “incomprehensible” world of materials is the biggest challenge to the materials science community. To access the properties of the materials and to utilize them for positive changes in the world are of great interest. Often scientists use approximate theories to get legitimate answers to the problems. Density functional theory (DFT) has emerged as one of the successful and powerful predictive methods in this regard. The accuracy of DFT relies on the approximate form of the exchange-correlation (EXC) functional. The most complicated form of this functional can be as accurate as more complicated and computationally robust method like Quantum Monte Carlo (QMC), Random Phase Approximation (RPA). Two newest meta-GGAs, SCAN and SCAN+rVV10 are among those functionals. Instantaneous charge fluctuation between any two objects gives rise to the van der Waals (vdW) interactions (often termed as dispersion interactions). It is a purely correlation effect of the interacting electrons and thus non-local in nature. Despite its small magnitude it plays a very important role in many systems such as weakly bound rare-gas dimers, molecular crystals, and molecule-surface interaction. The traditional semi-local functionals can not describe the non-local of vdW interactions; only short- and intermediate-range of the vdW are accounted for in these functionals. In this thesis we investigate the effect of the weak vdW interactions in surface properties, rare-gas dimers and how it can be captured seamlessly within the semi-local density functional approximation. We have used summed-up vdW series within the spherical-shell approximation to develop a new vdW correction to the meta-GGA-MS2 functional. This method has been utilized to calculate binding energy and equilibrium binding distance of different homo- and hetero-dimers and we found that this method systematically improves the MGGA-MS2 results with a very good agreement with the experimental data. The binding energy curves are plotted using this MGGA-MS2, MGGA-MS2-vdW and two other popular vdW-corrected functionals PBE-D2, vdW-DF2. From these plots it is clear that our summed-up vdW series captures the long-range part of the binding energy curve via C6, C8, and, C10 coefficients. The clean metallic surface properties such as surface energy, work functions are important and often play a crucial role in many catalytic reactions. The weak dispersion interactions present between the surfaces has significant effect on these properties. We used LDA, PBE, PBSEsol, SCAN and SCAN+rVV10 to compute the clean metallic surface properties. The SCAN+rVV10 seamlessly captures different ranges of the vdW interactions at the surface and predicts very accurate values of surface energy ( ) , and work function (𝞥) and inter-layer relaxations (𝞭%). Our conclusion is adding non-local vdW correction to a good semi-local density functional such as SCAN is necessary in order to predict the weak attractive vdW forces at the metallic surface. The SCAN+rVV10 has also been employed to study the hydrogen evolution reaction (HER) on 1T-MoS2. We have chosen as a descriptor differential Gibbs free energy (𝚫 GH ) to understand the underlying mechanism of this catalytic reaction. Density functional theory calculations agree with the experimental findings. In the case of layered materials like 1T-MoS2, vdW interactions play an important role in hydrogen binding, that SCAN+rVV10 calculation was able to describe precisely. We have also used SCAN and SCAN+rVV10 functionals to understand bonding of CO on (111) metal surfaces, where many approximations to DFT fail to predict correct adsorption site and adsorption energy. In this case SCAN and SCAN+rVV10 do not show systematic improvements compared to LDA or PBE, rather, both SCAN and SCAN+rVV10 overbind CO more compared to PBE but less compared to the LDA. This overbinding of CO is associated with the incorrect charge transfer from metal to molecule and presumably comes from the density-driven self-interaction error of the functionals. In this thesis we assessed different semi-local functionals to investigate molecule surface systems of 𝞹-conjugated molecules (thiophene, pyridine) adsorbed on Cu(111), Cu(110), Cu(100) surfaces. We find the binding mechanism of these molecules on the metallic surface is mediated by short and intermediate range vdW interactions. Calculated values of binding energies and adsorbed geometries imply that this kind of adsorption falls in the weak chemisorption regime. Structural phase transitions due to applied pressure are very important in materials science. However, pressure induced structural phase transition in early lanthanide elements such as Ce are considered as abnormal first order phase transition. The Ce 𝝰-to-𝝲 isostructural phase transition is one of them. The volume collapse and change of magnetic properties associated with this transition are mediated by the localized f-electron. Semi-local density functionals like LDA, GGA delocalize this f-electron due to the inherent self-interaction error (SIE) of these functionals. We have tested the SCAN functional for this particular problem, and, it was found that the spin-orbit coupling calculations with SCAN not only predicts the correct magnetic ordering of the two phases, but also gives a correct minima for the high-pressure 𝝰-Ce phase and a shoulder for the low-pressure 𝝲-Ce phase.
Temple University--Theses
Asiaee, Sahneh Sharareh Alsadat [Verfasser]. "Phase Transition Behavior and Application of Novel Surface-attached Thermo-responsive Polymer Films / Sharareh Alsadat Asiaee Sahneh." München : Verlag Dr. Hut, 2016. http://d-nb.info/1122524374/34.
Full textKoda, Ryo. "Electrochemical deposition of metal on microporous silicon electrodes influenced by hydration structures of solutes and electrode surfaces." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199323.
Full textLomello, Fernando. "Optimization of nanostructured oxide-based powders by surface modification." Lyon, INSA, 2010. http://theses.insa-lyon.fr/publication/2010ISAL0028/these.pdf.
Full textPortier, Fabien. "Etude expérimentale de deux systèmes élastiques bidimensionnels : électrons à la surface de l'hélium superfluide et vortex dans BSCCO (2212)." Paris 6, 2002. http://www.theses.fr/2002PA066461.
Full textPisztora, Ágoston. "Surface order large deviation behavior of the ising model in the phase transition regime : a Fortuin-Kasteleyn percolation analysis /." [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10286.
Full textHouchmandzadeh, Bahram. "Contribution à l'étude des transitions de phase dans les lignes et interfaces." Grenoble 1, 1992. http://www.theses.fr/1992GRE10042.
Full textDauzat, Marc. "Évolution thermique des alumines de transition. Modélisation." Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1989. http://tel.archives-ouvertes.fr/tel-00845199.
Full textAdawi, Hind. "Surface Effect Of Ferromagnetic Nanoparticles On Transition Between Single- And Multi-Domain Structure Or Between Single-Domain Structure And Superparamagnetic Phase." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1484061850635516.
Full textSigurbjornsson, Omar Freyr. "Vibrational dynamics of icy aerosol particles : phase transitions and intrinsic particle properties." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2795.
Full textWalczak, Malgorzata. "Role and properties of the confined amorphous phase of polymers." Phd thesis, Paris, ENSAM, 2012. http://pastel.archives-ouvertes.fr/pastel-00839174.
Full textDrilleau, Mélanie. "Une approche bayésienne pour estimer les propriétés physiques dans la zone de transition à partir des ondes de surface." Nantes, 2013. http://www.theses.fr/2013NANT2014.
Full textThe new tomographic methods involving 3-D kernel computations often use, as reference models, 3-D large wavelength VP , VS models obtained by linearized inversions. These models are based on small perturbations of 1-D global models and are secondly used to derive temperature and composition distributions. From a seismological point of view, the degree of heterogeneity in the transition zone (350- 1000 km depth), due to phase transitions and convective motions, can be strong enough that the concept of a 1-D reference seismic model might be addressed. A Markov chain Monte Carlo algorithm was implemented. This directly determines the statistical thermal state and anisotropic structure of the mantle from the dispersion data of Love and Rayleigh surface waves. Polynomial Bézier curves are chosen for the parameterization and are able to explore both smoothly varying models and first-order discontinuities. The solution is described in probabilistic terms, allowing uncertainties to be fully accounted for. The method is illustrated with both synthetic data and real dispersion curves. The results indicate a complex temperature distribution in the mid-transition zone beneath the Pacific Ocean. The retrieved anisotropy structure agrees with previous studies indicating positive uppermost mantle anisotropy. Considering few a priori conditions, the transition zone appears to be isotropic, along the investigated path
Nemitz, Ian Robert. "Cristaux liquides : surfaces, nanostructures et chiralité." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066586/document.
Full textThis dissertation focuses on liquid crystals (LCs), specifically their chiral properties and interactions with surfaces and nanostructures. Nematic twist cells were filled with a LC doped with the chiral molecule CB15, which compensates for the imposed twist. Using the electroclinic effect (ECE), results indicate that an ECE always exists near the surface in twist cells containing conformationally deracemizable molecules. ECE measurements were also performed to determine the source of the ECE response in a LC doped with chiral periodic mesoporous organosilica (PMO). The data show that the main source of the signal emanates from outside the PMO, and not inside the PMO pores. An ECE also is reported for chiral LCs above their bulk chiral isotropic–nematic phase transition, and is observable in the paranematic layers induced by the planar-aligning substrates. Optical microscopy measurements were performed on smectic-A oily streaks doped with CB15. When chirally doped, the stripe orientation rotated by a temperature dependent angle: This angle increased with concentration, was largest just below the nematic – smectic-A transition, and stabilized to near zero within ~1C below TNA. This is explained as a manifestation of a surface ECE. Finally, a novel structure in a hybrid aligned system was observed below the Smectic-A – Smectic-C transition. The structure appeared as periodic dark and light streaks running perpendicular to the oily streaks, and formed by extending discretely from one oily streak to the next, eliminating optical evidence of the oily streaks. At lower temperatures the streaks undulated in a 2D chiral pattern. A possible origin of these streaks is presented
Ni, Suolong. "Poly(L-Lactic Acid) Langmuir Monolayers at the Air/Water Interface and Langmuir-Blodgett Films on Solid Substrates: Phase Behavior, Surface Morphology, and Crystallinity." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/30094.
Full textPh. D.
Ouerghi, Abdelkarim. "Croissance épitaxiale de MnAs sur GaAs(111) et étude des reconstructions de la surface de MnAs." Paris 6, 2004. http://www.theses.fr/2004PA066568.
Full textAbdul, Kader Khaldoun. "Étude du phénomène de la transition de spin dans les couches ultra-minces à l'aide des plasmons de surface." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2349/.
Full textRecently, nano-objects and thin films displaying molecular spin crossover phenomenon have attracted much attention for their possible application as an active element in electronic or photonic devices. The change of the spin state is accompanied by a change in various physical properties of this molecule such as magnetic, optical, electrical and mechanical properties. However, the detection of the spin crossover in these materials at the nanoscale (thin films, nanoparticles,. . . ) makes for great difficulties, due to the small amount of the probed material, as well as due to the limited spatial resolution of the usual detection methods. To overcome these problems new methods have been developed in this thesis to study these materials at the nanoscale. Our approach is based on the resonance phenomena of localised surface plasmons and surface plasmon polaritons. These techniques use thin noble metal layers or patterned nanorod arrays, which allowed us to detect the refractive index change accompanying the spin crossover. In this thesis work, for the first time, we have been able to detect the spin crossover phenomenon in nanometric layers (down to 15 nm) for different materials, highlighting a refractive index variation of 10-1 - 10-2. In addition, we have shown that the molecular spin state switching can be very efficiently triggered by a photo-thermal effect (plasmonic heating), which - in turn - allows for an active tuning of the plasmon resonance
Lerouge, Sandra. "Transitions de phases induites par écoulement dans les systèmes de micelles géantes : étude optique et rhéologique." Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Lerouge.Sandra.SMZ0037.pdf.
Full textSotiropoulou, Georgia. "The Arctic Atmosphere : Interactions between clouds, boundary-layer turbulence and large-scale circulation." Doctoral thesis, Stockholms universitet, Meteorologiska institutionen (MISU), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-134525.
Full textAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.
Li, Linjun. "Systems Driven out of Equilibrium with Energy Input at Interfaces or Boundaries." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/77884.
Full textPh. D.
Fillon, Amélie. "Interdépendance entre contraintes, transition de phase et nanostructure lors de la croissance par pulvérisation magnétron de films métalliques : application au système Mo/Si." Phd thesis, Université de Poitiers, 2010. http://tel.archives-ouvertes.fr/tel-00628047.
Full textCerchez, Vladimir. "Nano structures formed by molecular chlorine interaction with noble metal surfaces : scanning Tunneling Microscopy/Spectroscopy study." Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10047/document.
Full textThis work is related to the systematic study of chlorine adsorption mechanism on the metal's surfaces Au(111), Ag(111) and Cu(111). We had used for this study the interaction of chlorine gas with metal surface in ultra-high vacuum conditions. Elaborated systems were characterized from the structural point of view by low-energy electron diffraction and low-temperature scanning tunneling microscopy (5 K). Local electronic properties were probed by scanning tunneling spectroscopy. The first part of the work is devoted to the surface's structural modifications induced by chlorine adsorption from sub-monolayer regime to saturation, which corresponds to the appearance of metal halide precursors. From numerous experimental results we were able to describe in details the mechanism of gas/surface interaction and to propose atomic structural models that remained unresolved up to now. The proposed models were validated by density functional theory calculations. The second part of the thesis is devoted to the study of original electronic properties of the superstructure of quantum wells formed by self-organization of chlorine atoms on (111) surface of gold. We had studied the quantum resonances that appeared due to the confinement of surface electronic states in the pores of few nanometers in diameter. The eigenstates were characterized as a function of the quantum well?s shape and size. This study was completed by numerical modeling of spectroscopic properties of nano-pores in the "particle-in-a-box" limit
Gonçalves, Luis Gustavo Vieira. "Estudo da fusão de superfície da prata por dinâmica molecular." Universidade Federal de São Carlos, 2008. https://repositorio.ufscar.br/handle/ufscar/5004.
Full textFinanciadora de Estudos e Projetos
A study about surface melting on silver using equilibrium molecular dynamics simulation is the proposal of this work. We applied the Embedded Atom Method as the many-body interaction potential to describe Ag properties. Simulations were done in the microcanonical ensemble, for the study of bulk properties, and in the canonical ensemble, for simulations of the solid with surfaces. As a preliminary result, we obtained the equilibrium melting point Tm equal 1264(12)K from solid-liquid coexistence configurations. Surfaces were simulated using repeated slabs separated by vacuum in the z direction, while keeping periodic boundary conditions in the remaining directions. Results showed that Ag[110] is the lone orientation that has surface melting. Ag[111] maintains its crystalline structure even after reaching Tm, while it could be overheated by 100K. Other properties like density of states, thermal expansion and surface relaxation were in good agreement with experimental data.
Um estudo sobre a fusão de superfícies da prata (Ag) utilizando dinâmica molecular de equilíbrio é a proposta deste trabalho. Aplicamos o método Embedded Atom como potencial de interação de muitos corpos para descrever as propriedades da prata. As simulações foram feitas nos ensembles microcanônico, para o estudo de propriedades de bulk, e canônico, para as simulações do sólido com superfícies. Como resultado de estudo preliminar, obtivemos a temperatura de fusão de equilíbrio Tm igual a 1264(12)K a partir das configurações do sistema com as fases sólida e líquida em coexistência. As superfícies foram simuladas incluindo uma separação com vácuo acima e abaixo do cristal na direção z e utilizando condições periódicas de contorno nas outras direções cartesianas. Os resultados mostraram que a superfície [110] é a única que possui fusão de superfície. A superfície [111] mantém sua estrutura cristalina até mesmo após atingir Tm, podendo esse sistema ser superaquecido em 100K. Outras propriedades como densidade de estados, dilatação térmica e relaxação de superfície tiveram boa concordância com os dados obtidos experimentalmente.
Bertosio, Jean-Marc. "Caractérisation de surfaces métalliques et de couches minces par diffusion d'atomes d'hélium : application au système Pb/Cu(110)." Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL133N.
Full textSwift, Michael Robert. "Surface phase transitions in novel geometries." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279938.
Full textBraun, Frank Nicholas. "Surface phase transitions in liquid crystals." Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242564.
Full textGelb, Lev. "Theoretical studies of surface phase transitions." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387600.
Full textLusk, Mark T. Knowles James K. "Martensitic phase transitions with surface effects /." Diss., Pasadena, Calif. : California Institute of Technology, 1992. http://resolver.caltech.edu/CaltechETD:etd-11052004-161432.
Full textBiage, Milton. "Structure de la surface libre d'un film liquide ruisselant sur une plaque plane verticale et soumis à un contre-courant de gaz : transition vers l'écoulement cocourant ascendant." Grenoble INPG, 1989. http://www.theses.fr/1989INPG0053.
Full textHassenforder, Philippe. "Preparation et etude de couches minces cristallines de polydiacetylenes." Paris 6, 1988. http://www.theses.fr/1988PA066289.
Full textGoapper, Sylvain. "Morphologie de surface et ordre chimique : Faces vicinales d'alliage cuivre-palladium." Phd thesis, Université de Marne la Vallée, 1998. http://tel.archives-ouvertes.fr/tel-00243115.
Full textLa diffraction de rayons X à l'ESRF nous a permis d'observer l'apparition du désordre chimique à la surface et l'évolution simultanée du changement de structure des marches. On observe que la séparation des paires de marches évolue proportionnellement à la composante parallèle du paramètre d'ordre dans le plan de surface.
Pour des temps courts de mise en ordre, le STM montre une structure en domaines, des marches appariées. On identifie les frontières entre domaines par le dédoublement local des paires de marches. Ce phénomène traduit l'émergence à la surface de parois. Cette structure en domaine, caractéristique de l'ordre chimique dans les premiers plans de surface, nous a permis, par STM et diffraction d'hélium, de suivre la cinétique de mise en ordre en présence d'une surface. La taille caractéristique des domaines évolue avec le temps de recuit en A(T).t1/2. Un diagramme d'Arrhénius du facteur d'échelle temporel A(T) a permis de mesurer une énergie d'activation de mise en ordre de 2 eV à la surface ainsi qu'en volume.
Dans une seconde étude, nous avons caractérisé l'influence du dépôt de palladium sur une surface vicinale de cuivre. Nous avons montré par diffraction d'hélium que cet alliage de surface provoque un appariement des marches similaires à celles observées sur l'alliage massif Cu3Pd. Cependant, cette modification de la distribution des marches présente un faible degré d'ordre qui peut être du à l'absence d'ordre chimique à longue distance.
Salimi, Abdelhadi. "Etude par spectrométrie de vibration de cristaux liquides de la famille des cyano-4 alkyl ou alcoxyl-4' biphényles : évolution conformationnelle et transition de phase en fonction de la pression, couches ultraminces sur surface d'or." Bordeaux 1, 1990. http://www.theses.fr/1990BOR10523.
Full textWoollacott, Claire. "Electronic and plasmonic properties of real and artificial Dirac materials." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/18227.
Full textGuyot, Hervé. "Etude des transitions d'onde de densité de charge et des propriétés de transport des oxydes de molybdène [êta]-Mo4O11 et [gamma]-Mo4O11." Grenoble 1, 1986. http://www.theses.fr/1986GRE10122.
Full textZerrouk, Taha-El-Amine. "Phase transitions of xenon adsorbed on graphite." Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333446.
Full textLintz, Michel. "MESURE DE LA VIOLATION DE LA PARITE SUR LA TRANSITION 6S-7S DU CESIUM PAREMISSION STIMULEE DANS UNE VAPEUR ATOMIQUE." Habilitation à diriger des recherches, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00011127.
Full textVIELZA, DE LA CRUZ Yoandris. "Evolução da superfície de Fermi do La2-xSrxCuO4: estados locais de Wannier/Hartree-Fock." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18562.
Full textMade available in DSpace on 2017-04-17T18:48:07Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação Mestrado.pdf: 3421668 bytes, checksum: 4a6d6f2568841028e0b66b952f2d15ba (MD5) Previous issue date: 2016-08-30
Este trabalho é uma extensão de uma modelagem tight−binding de estados de Wannier com interação coulombiana de screening para a descrição de elétrons correlacionados nas camadas de CuO2 do La2CuO4. Na condição de banda semicheia e temperatura T = 0 K, esta modelagem é capaz de predizer um estado fundamental antiferromagnético isolante e um estado excitado paramagnético com pseudo-gap, cuja natureza ainda é debatido na literatura. Esses estados são obtidos no contexto de uma solução auto-consistente tipo Hartree-Fock na modelagem de uma banda efetiva de estados de Wannier, sob condições de quebra de simetria de translações espaciais e efeito de emaranhamento (entanglement) na estrutura espinorial dos estados eletrônicos. No regime dopado com buracos, esses estados ficam degenerados num ponto crítico de concentração de buracos igual a xc = 0.2, resultando em uma transição de fase quântica de segunda ordem para um estado paramagnético. A modelagem dá assim explicação à existência detectada experimentalmente desta transição de fase. Em nosso trabalho generalizamos o termo cinético da modelagem acima mencionada através da inclusão de hopping entre segundos vizinhos, de acordo com observações experimentais. De fato, a inclusão deste novo termo cinético resulta em melhor concordância da previsão da modelagem e as observações experimentais da evolução da superfície de Fermi com dopagem de buracos. Em particular, enquanto na modelagem restrita a primeiros vizinhos não podemos conciliar a transição de fase quântica observada a xc = 0.2 com as características experimentais da evolução da superfície de Fermi, isto torna-se possível com a inclusão do hopping de segundos vizinhos com amplitude sugerida pelos resultados experimentais.
This work is an extension of a tight - binding model of states of Wannier with screened Coulomb interaction to the description of correlated electrons in the layers of CuO2 of the La2CuO4. In condition of half-filled band and temperature T = 0 K, this model is able to predict a antiferromagnetic insulating ground state and a paramagnetic excited state with pseudo-gap, which nature is still debated in the literature. These states are obtained in the context of a self-consistent solution type Hartree-Fock in the model of an effective band of the Wannier states under breaking conditions of symmetry of space translations and entanglement effect in the spinor structure of the electronic states. In scheme doped with holes, these states are degenerate at critical point of hole concentration equal to xc = 0.2, resulting in a quantum phase transition of second order to paramagnetic state. The model thus gives explanation to the existence of this experimentally detected phase transition. In our work we generalize the kinetic term of above mentioned model by inclusion of hopping between seconds neighboring, according to experimental observations. In fact, the inclusion of this new kinetic term results in better agreement of the forecast of the model and experimental observations of the evolution of the Fermi surface with holes doping. In particular, while the model is restricted to the first neighbors can not reconcile quantum phase transition observed at xc = 0.2 with the experimental characteristics of the evolution of the Fermi surface, this becomes possible with the inclusion of hopping between second neighboring with ampliude suggested by experimental results.
Casson, Brian Derek. "Phase transitions in surfactant monolayers." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300797.
Full textGeoghegan, Mark. "Surface induced phase transitions in thin polymer blend films." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319888.
Full textSahli, Salah. "Etude du comportement electrique de films minces de gaas amorphes ou polycristallins elabores par depots en phase vapeur ou par plasma a partir d'organometalliques." Toulouse 3, 1986. http://www.theses.fr/1986TOU30049.
Full textGuerrisi, Burger Catherine. "Intéractions électrolytes 1:1 surfactants non-ioniques polyoxyéthyles et influence sur les zones d'existence de phases microémulsions fluoro-carbonées : Étude de quelques transitions structurales dans ces phases." Nancy 1, 1987. http://www.theses.fr/1987NAN10081.
Full textImpéror-Clerc, Marianne. "Étude de transition de phase vers les phases cubiques des systèmes eau/surfactant." Paris 11, 1992. https://tel.archives-ouvertes.fr/tel-01989797.
Full textCapitolis, Jérôme. "Synthèse de nanoparticules d'oxydes de titane ou de vanadium à basse valence." Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS499.pdf.
Full textThis PhD work deals with the development of new synthesis pathways for low valence titanium or vanadium oxide nanoparticles. These oxides are attracting an increasing interest for applications such as thermoelectricity, data or energy storage, especially at the nanoscale where performances can be enhanced. However the synthesis of these solids at nanoscale is a challenge. In this work, the synthesis of nanoparticles of several low or mixed valence titanium oxides is studied. The approach that are explored are based on the reduction of titanium dioxide nanoparticles by metallic hydrides in molten salts. It enables control over phase, size and morphology of the nanoparticles. The synthesis of V2O3 nanoparticles from molecular precursors in molten salts has also been developed, in order to control the structure, size and morphology of the nanoparticles. This pathway enables the synthesis of a non-identified vanadium containing oxide and lays the foundation for the synthesis of vanadium Magnéli phases at the nanoscale. Finally the surface reactivity of nanoparticles of Ti4O7 and Ti6O11 Magnéli phases were explored by Near ambient pressure-X ray photoelectron spectroscopy
Ropers, Marie-Hélène. "Étude structurale de Systèmes Moléculaires Organisés à base de tensioactifs fluorés non ioniques : application à l'immobilisation de biomolécules." Nancy 1, 2000. https://hal.univ-lorraine.fr/tel-01746458.
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