Theoretical study of interacting electrons in one dimension - ground states and experimental signatures

TL;DR

This paper provides a theoretical analysis of interacting electrons in one-dimensional systems, revealing ground state phases, superconductivity with finite momentum pairing, and spectral features indicative of spin-charge separation.

Contribution

It introduces a detailed theoretical framework for understanding ground states, superconductivity, and spectral signatures in one-dimensional electron liquids, especially in aluminum arsenide quantum wires.

Findings

Existence of a spin gapped quantum wire with charge density wave and singlet superconductivity.

Prediction of a Fulde-Ferrell-Larkin-Ovchinnikov state with finite momentum Cooper pairs.

Identification of a kink in the spectral function as a signature of spin-charge separation.

Abstract

This dissertation focuses on a theoretical study of interacting electrons in one dimension. The research elucidates the ground state (zero temperature) electronic phase diagram of an aluminum arsenide quantum wire which is an example of an interacting one dimensional electron liquid. Using one dimensional field theoretic methods involving abelian bosonization and the renormalization group we show the existence of a spin gapped quantum wire with electronic ground states such as charge density wave and singlet superconductivity. The superconducting state arises due to the unique umklapp interaction present in the aluminum arsenide quantum wire bandstructure discussed in this dissertation. It is characterized by Cooper pairs carrying a finite pairing momentum. This is a realization of the Fulde-Ferrell-Larkin- Ovchinnikov state which is known to lead to inhomogeneous superconductivity. The dissertation also presents a theoretical analysis of the finite temperature single hole spectral function of the one dimensional electron liquid with gapless spin and charge modes (Luttinger liquid). The hole spectral function is measured in angle resolved photoemission spectroscopy experiments. The results predict a kink in the effective electronic dispersion of the Luttinger liquid. A systematic study of the temperature and interaction dependence of the kink provides an alternative way to detect spincharge separation in one dimensional systems where the peak due to the spin part of the spectral function is suppressed.