Effects of electron-electron and electron-phonon interactions in narrow-band systems.

Persistent Link:
http://hdl.handle.net/10150/186622
Title:
Effects of electron-electron and electron-phonon interactions in narrow-band systems.
Author:
Ung, Kim-Chau.
Issue Date:
1994
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Different ordered states, CDW, BOW, and SDW, are investigated theoretically for both interacting and noninteracting cases as well as for different band filling systems. For noninteracting case, we find that the BOW is always accompanied by the CDW and vice versa in one-dimensional system for commensurability > 2. The strong electron-molecular vibration coupling drives both CDW and BOW, and plays thus an important role in the stabilization of the CDW state for these non-half-filled materials. Within the simply extended Peierls-Hubbard model, the experimentally observed lattice distortion of MEM(TCNQ)₂ can be precisely understood with our model calculation. In addition to the on-site repulsion U, the nearest-neighbor Coulomb interaction V is shown to play a vital role in the strongly correlated system; and a critical value V(c) is found for the quarter-filled system. With the understanding of the dominant broken symmetries in quasi-one-dimensional quarter-filled band, some implications for superconducting materials are discussed. The effect of band filling on the 4k(F) BOW instability is studied by the extended Peierls-Hubbard model; it is found that a strongly systematic tendency of the 4k(F) is dependent on the band filling. By studying the pair binding energy in some small clusters, we point out that the electron (or hole) pairing is not due to the Coulomb interaction, at least in the small U region.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Dissertations, Academic.; Physics.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Physics; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Mazumdar, Sumitendra

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleEffects of electron-electron and electron-phonon interactions in narrow-band systems.en_US
dc.creatorUng, Kim-Chau.en_US
dc.contributor.authorUng, Kim-Chau.en_US
dc.date.issued1994en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractDifferent ordered states, CDW, BOW, and SDW, are investigated theoretically for both interacting and noninteracting cases as well as for different band filling systems. For noninteracting case, we find that the BOW is always accompanied by the CDW and vice versa in one-dimensional system for commensurability > 2. The strong electron-molecular vibration coupling drives both CDW and BOW, and plays thus an important role in the stabilization of the CDW state for these non-half-filled materials. Within the simply extended Peierls-Hubbard model, the experimentally observed lattice distortion of MEM(TCNQ)₂ can be precisely understood with our model calculation. In addition to the on-site repulsion U, the nearest-neighbor Coulomb interaction V is shown to play a vital role in the strongly correlated system; and a critical value V(c) is found for the quarter-filled system. With the understanding of the dominant broken symmetries in quasi-one-dimensional quarter-filled band, some implications for superconducting materials are discussed. The effect of band filling on the 4k(F) BOW instability is studied by the extended Peierls-Hubbard model; it is found that a strongly systematic tendency of the 4k(F) is dependent on the band filling. By studying the pair binding energy in some small clusters, we point out that the electron (or hole) pairing is not due to the Coulomb interaction, at least in the small U region.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectDissertations, Academic.en_US
dc.subjectPhysics.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairMazumdar, Sumitendraen_US
dc.contributor.committeememberGarcia, J.D.en_US
dc.contributor.committeememberParmenter, R.H.en_US
dc.contributor.committeememberStark, R.M.en_US
dc.contributor.committeememberToussaint, Den_US
dc.identifier.proquest9424956en_US
dc.identifier.oclc722419175en_US
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