The Extended Hubbard Model: Theory, Simulations, and Applications

Clay, Rudolf Torsten

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Description

Title

The Extended Hubbard Model: Theory, Simulations, and Applications

Author(s)

Clay, Rudolf Torsten

Issue Date

1999

Doctoral Committee Chair(s)

David K. Campbell

Department of Study

Physics

Discipline

Physics

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Physics, Condensed Matter

Language

eng

Abstract

The Hubbard model is one of the most widely studied many-body models for interacting electrons in solids. Here we present a study of the Extended Hubbard model, which provides a more realistic description of real materials by including some longer-range Coulomb interactions. We discuss the derivation of the model, numerical methods for many-body systems, the ground state of the one-dimensional model, and an application of the model to organic charge-transfer solids. Our discussion of numerical methods includes details of using the Constrained Path Monte Carlo procedure to treat extended interactions and possible extension of the method for imaginary times. The chapter on the one-dimensional model focuses on the region V>U, where previous work had suggested the possibility of superconductivity. Our results show that instead phase separation is prevalent in that parameter regime. The second application is to model the organic charge-transfer salts, which are intermediate between one and two dimensions. Here we find a coexistence of charge and spin ordering that helps to explain the results of recent experiments on these materials.

Graduation Semester

1999

Type of Resource

text

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http://hdl.handle.net/2142/80674

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