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Anistropic phenomena in strongly correlated electron systems

Carter, Edwin Christopher (2005)
Ph.D. thesis, University of Birmingham.

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Abstract

This thesis is concerned with momentum anisotropy in strongly correlated electron systems, and explores its origin and its consequences through two contrasting projects. The first is a study of the temperature dependences of magnetotransport quantities in the normal state of the cuprate high-temperature superconductors. A phenomenological anisotropic small-angle scattering model is investigated; Hall effect measurements can be reproduced for parameters sufficiently close to particle-hole symmetry, but the experimentally observed magnetoresistance cannot be explained. The second project studies the phase diagram and quasiparticle properties of the square lattice Hubbard model within two-site cluster dynamical mean field theory (DMFT), at zero temperature. The "two-site" approach provides a drastically simplified but physically motivated self-consistency scheme for DMFT. This is combined for the first time with cluster DMFT, within which different magnetic orders and momentum anisotropy may be represented consistently. The extent of antiferromagnetism is determined; phases are discovered where the Fermi surface consists of small hole pockets, and the Mott transition happens as these pockets shrink to points. Anisotropic phenomena observed in the cuprates are reproduced by the theory; a pseudogap destroys the Fermi surface in some places, leaving behind Fermi arcs that closed into hole pockets by lines with very small quasiparticle residue.

Type of Work:Ph.D. thesis.
Supervisor(s):Schofield, Andrew J.
School/Faculty:Schools (1998 to 2008) > School of Physics & Astronomy
Department:Physics
Keywords:Magnetotransport, cuprate high-temperature superconductors, two-site cluster DMFT, pseudogap
Subjects:QC Physics
Institution:University of Birmingham
Library Catalogue:Check for printed version of this thesis
ID Code:83
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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