Localization in an Inhomogeneous Quantum Wire

TL;DR

This paper investigates how electron localization occurs in an inhomogeneous quantum wire with varying density regions, using Quantum Monte Carlo methods to understand the transition and effects like Coulomb blockade.

Contribution

It introduces a detailed analysis of interaction-induced localization in an inhomogeneous wire, highlighting the role of density gradients and ruling out ferromagnetic polarization.

Findings

Localization occurs in low-density regions due to Coulomb interactions

Steep density gradients lead to Coulomb blockade effects

No ferromagnetic spin polarization observed in studied parameters

Abstract

We study interaction-induced localization of electrons in an inhomogeneous quasi-one-dimensional system--a wire with two regions, one at low density and the other high. Quantum Monte Carlo techniques are used to treat the strong Coulomb interactions in the low density region, where localization of electrons occurs. The nature of the transition from high to low density depends on the density gradient--if it is steep, a barrier develops between the two regions, causing Coulomb blockade effects. Ferromagnetic spin polarization does not appear for any parameters studied. The picture emerging here is in good agreement with measurements of tunneling between two wires.