Award Date

1-1-2000

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

First Committee Member

Changfeng Chen

Number of Pages

69

Abstract

The goal of this project is to study the ground-state properties of frustrated spin-1/2 two- and three-leg Heisenberg ladders, and to investigate possible effects of diagonal couplings on spin gaps. The ground-state and the first-excited-state energies of these two systems are calculated systematically by using the density matrix renormalization group method. The ground state phase diagrams for these two systems are obtained. For the frustrated two-leg ladder, we found that the spin gap is insensitive to the change of the FM diagonal coupling constant. This is in agreement with experimental suggestions. For the frustrated three-leg ladder, we conclusively proved that introducing AF diagonal couplings can not change the gapless property of the ground state.

Keywords

Antiferromagnetic; Frustrated; Heisenberg; Heisenberg Ladders; Ladders; Leg; Phase Diagrams; Spin; Spin-1/2

Controlled Subject

Condensed matter; Physics

File Format

pdf

File Size

2017.28 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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