Resonant reflection at magnetic barriers in quantum wires

TL;DR

This paper investigates how magnetic barriers affect conductance in quantum wires, revealing Fano-type resonances caused by vortex-like quasibound states and showing disorder's impact on conductance near pinch-off.

Contribution

It introduces a numerical study of magnetic barrier effects in quantum wires, identifying vortex-type quasibound states responsible for Fano resonances and analyzing disorder effects.

Findings

Fano-type reflection resonances occur near pinch-off in strong magnetic barriers.

Vortex-type quasibound states inside the magnetic barrier cause interference effects.

Disorder significantly alters conductance around the pinch-off regime.

Abstract

The conductance of a quantum wire containing a single magnetic barrier is studied numerically by means of the recursive Greens function technique. For sufficiently strong and localized barriers, Fano - type reflection resonances are observed close to the pinch-off regime. They are attributed to a magnetoelectric vortex-type quasibound state inside the magnetic barrier that interferes with an extended mode outside. We furthermore show that disorder can substantially modify the residual conductance around the pinch-off regime.