Spin-orbit coupling and resonances in the conductance of quantum wires

TL;DR

This paper explores how spin-orbit coupling in quantum wires enables electron-electron collisions that affect conductance, revealing resonant behaviors and explaining recent experimental features in InAs wires.

Contribution

It demonstrates that spin-orbit coupling creates finite phase space for electron collisions, leading to conductance resonances dependent on wire symmetry and temperature.

Findings

Resonant conductance contributions depend on spin-splitting and spin precession.

Resonances exhibit different power-law temperature dependencies.

Symmetric confinement can suppress certain collision-induced conductance features.

Abstract

We investigate a possibility of pair electron-electron e-e collisions in a ballistic wire with spin-orbit coupling and only one populated mode. Unlike in a spin-degenerate system, a combination of spin-splitting in momentum space with a momentum-dependent spin-precession opens up a finite phase space for pair e-e collisions around three distinct positions of the wire's chemical potential. For a short wire, we calculate corresponding resonant contributions to the conductance, which have different power-law temperature dependencies, and, in some cases, vanish if the wire's transverse confinement potential is symmetric. Our results may explain the recently observed feature at the lower conductance plateau in InAs wires.