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dc.contributor.advisorHetenyi, Balazsen_US
dc.contributor.authorSaleem, Luqmanen_US
dc.date.accessioned2018-09-18T07:32:06Z
dc.date.available2018-09-18T07:32:06Z
dc.date.copyright2018-09
dc.date.issued2018-09
dc.date.submitted2018-09-17
dc.identifier.urihttp://hdl.handle.net/11693/47885
dc.descriptionCataloged from PDF version of article.en_US
dc.descriptionThesis (M.S.): Bilkent University, Department of Physics, İhsan Doğramacı Bilkent University, 2018en_US
dc.descriptionIncludes bibliographical references (leaves 55-58).en_US
dc.description.abstractThe interacting Su-Schrieffer-Heeger model with nearest neighbor interaction in one dimension at half-filling is studied. To obtain ground state wave function, the Baeriswyl variational wave function is extended to account for alternating hopping parameters. The ground state energy is numerically calculated and compared with exact diagonalization calculations, finding excellent agreement. Full phase diagram of the model is constructed which shows three different phases. When all hopping parameters are same the ideal metal-insulator phase transition is found at finite interaction, somewhat less than the exact results. The conducting phase is a Fermi sea. The phase transitions found are first order. With alternating hopping parameters the small interaction phase is the ground state of the Su- Schrieffer-Heeger model and the large interactions phase is an insulator. The phase transition has been visualized by constructing the parent Hamiltonian of the ground state wave function and tracing out the curves of the Brillouin zone. The polarization distribution is reconstructed from its cumulants on two different paths taken in the parametric space of interaction and hopping parameter. The first path is taken as it crosses the metallic phase line while the other path makes a semi-ellipse avoiding the metallic line. In the former case, the distribution is centered at one site and discontinuously jumps to the next site after crossing the metallic phase line, while in latter case distribution walks smoothly from one site to the next. These results suggest that interaction breaks the chiral symmetry of the Su-Schrieffer-Heeger model, in the same way as on-site potential breaks it in Rice-Mele model.en_US
dc.description.statementofresponsibilityby Luqman Saleem.en_US
dc.format.extentxii, 58 leaves : charts ; 30 cm.en_US
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectPhase Transitionen_US
dc.subjectLattice Modelsen_US
dc.subjectVariational Techniquesen_US
dc.subjectMany-Body Condensed Matter Approximationen_US
dc.subjectBaeriswyl Wave Functionen_US
dc.subjectElectric Polarizationen_US
dc.subjectBerry Phaseen_US
dc.titleVariational study of interacting su-schrieffer-heeger modelen_US
dc.title.alternativeEtkileşen su-schrieffer-heeger modelin varyasyonel çalışmasıen_US
dc.typeThesisen_US
dc.departmentDepartment of Physicsen_US
dc.publisherBilkent Universityen_US
dc.description.degreeM.S.en_US
dc.identifier.itemidB159010


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