A Hartree-Fock Study of Persistent Currents in Disordered Rings

TL;DR

This study shows that the Hartree-Fock method effectively models the enhancement and charge reorganization of persistent currents in disordered mesoscopic rings with spinless fermions, aligning well with exact diagonalization results.

Contribution

It demonstrates the applicability of the Hartree-Fock approximation to analyze persistent currents and charge reorganization in disordered one-dimensional and coupled chain systems.

Findings

Hartree-Fock closely reproduces exact diagonalization results.

Persistent current derivative is discontinuous with respect to interaction strength U.

Charge reorganization significantly enhances persistent currents.

Abstract

For a system of spinless fermions in a disordered mesoscopic ring, interactions can give rise to an enhancement of the persistent current by orders of magnitude. The increase in the current is associated with a charge reorganization of the ground state. The interaction strength for which this reorganization takes place is sample-dependent and the log-averages over the ensemble are not representative. In this paper we demonstrate that the Hartree-Fock method closely reproduces results obtained by exact diagonalization. For spinless fermions subject to a short-range Coulomb repulsion U we show that due to charge reorganization the derivative of the persistent current is a discontinuous function of U. Having established that the Hartree-Fock method works well in one dimension, we present corresponding results for persistent currents in two coupled chains.