Nonreciprocal Charge and Spin Transport Induced by Non-Hermitian Skin Effect in Mesoscopic Heterojunctions

TL;DR

This paper demonstrates how non-Hermitian skin effect can be engineered in mesoscopic heterojunctions, leading to observable nonreciprocal charge and spin transport, opening new avenues for electronic device applications.

Contribution

It introduces a reservoir-engineered approach to realize and detect the non-Hermitian skin effect in electronic mesoscopic systems, a feat previously elusive in condensed matter physics.

Findings

Nonreciprocal charge current observed in mesoscopic heterojunctions.

Spin-resolved non-Hermitian skin effect demonstrated.

Potential for novel electronic device applications.

Abstract

The pursuit of the non-Hermitian skin effect (NHSE) in various physical systems is of great research interest. Compared with recent progress in non-electronic systems, the implementation of the NHSE in condensed matter physics remains elusive. Here, we show that the NHSE can be engineered in the mesoscopic heterojunctions (system plus reservoir) in which electrons in two channels of the system moving towards each other have asymmetric coupling to those of the reservoir. This makes electrons in the system moving forward and in the opposite direction have unequal lifetimes, and so gives rise to a point-gap spectral topology. Accordingly, the electron eigenstates exhibit NHSE under the open boundary condition, consistent with the description of the generalized Brillouin zone. Such a reservoir-engineered NHSE visibly manifests itself as the nonreciprocal charge current that can be probed by the standard transport measurements. Further, we generalize the scenario to the spin-resolved NHSE, which can be probed by the nonreciprocal spin transport. Our work opens a new research avenue for implementing and detecting the NHSE in electronic mesoscopic systems, which will lead to interesting device applications.