The effect of a local perturbation in a fermionic ladder

TL;DR

This paper investigates how a local external potential affects electron transport in a two-wire fermionic system, revealing that asymmetry in the potential can completely block conductance, which could be used for sensitive gradient detection.

Contribution

It demonstrates the impact of asymmetric local perturbations on transport in coupled nanowires, highlighting potential applications in local potential sensing.

Findings

Asymmetric potentials cause vanishing conductance at zero temperature.

Flat potentials remain transparent to electron transport.

Transport sensitivity depends on the transverse gradient of the perturbation.

Abstract

We study the effect of a local external potential on a system of two parallel spin-polarized nanowires placed close to each other. For single channel nanowires with repulsive interaction we find that transport properties of the system are highly sensitive to the transverse gradient of the perturbation: the asymmetric part completely reflects the electrons leading to vanishing conductance at zero temperature, while the flat potential remains transparent. We envisage a possible application of this unusual property in the sensitive measurement of local potential field gradients.