Correlations, inhomogeneous screening, and suppression of spin-splitting in quantum wires at strong magnetic fields

TL;DR

This paper presents a self-consistent theoretical study of many-body interactions in quantum wires under strong magnetic fields, revealing how correlations and inhomogeneous screening suppress spin-splitting and affect quantum Hall states.

Contribution

It introduces a modified local-density approximation and screened Hartree-Fock approach to accurately model spin-splitting suppression in quantum wires at high magnetic fields.

Findings

Correlations significantly suppress exchange spin-splitting.

Edge screening smoothens energy dispersion and reduces spin-splitting.

Theory matches experimental observations of spin-splitting suppression.

Abstract

A self-consistent treatment of exchange and correlation interactions in a quantum wire (QW) subject to a strong perpendicular magnetic field is presented using a modified local-density approximation (MLDA). The influence of many-body interactions on the spin-splitting between the two lowest Landau levels (LLs) is calculated within the screened Hartree-Fock approximation (SHFA), for filling factor \nu=1, and the strong spatial dependence of the screening properties of electrons is taken into account. In comparison with the Hartree-Fock result, the spatial behavior of the occupied LL in a QW is strongly modified when correlations are included. Correlations caused by screening at the edges strongly suppress the exchange splitting and smoothen the energy dispersion at the edges. The theory accounts well for the experimentally observed strong suppression of the spin-splitting pertinent to the \nu=1 quantum Hall effect (QHE) state as well as the destruction of this state in long, quasi-ballistic GaAlAs/GaAs QWs.