Fabry-P\'{e}rot interference in 2D low-density Rashba gas

TL;DR

This paper demonstrates that Fabry-Pérot oscillations can be observed in 2D low-density Rashba gases due to band structure effects, with enhanced visibility through interface barriers, expanding understanding of quantum interference in 2D systems.

Contribution

It generalizes the mechanism of FP oscillations from graphene and InAs/GaSb systems to low-density Rashba gases, highlighting the role of band shape and backscattering.

Findings

Backscattering between Fermi circles dominates FP interference.

Interface barriers enhance oscillation visibility.

Visible conductance oscillations are achievable in 2D Rashba gases.

Abstract

In mesoscopic electronic systems, the Fabry-P\'{e}rot (FP) oscillation is observed in various 1D devices. As for higher dimensions, numerous transverse channels usually lead to dephasing that quenches the overall oscillation of the conductance. Up to now, the FP oscillation in 2D electronic systems is only reported in graphene-based devices, and very recently, the \emph{pn} junctions of inverted InAs/GaSb double quantum well [Phys. Rev. X 10, 031007 (2020)]. In the latter, the band shape of a sombrero hat plays an essential role, which introduces a novel mechanism of electron-hole hybridization for the 2D FP oscillation. In this work, we propose that such a scenario can be generalized to the 2D planar junction composed of low-density Rashba gas, where the band bottom possesses a sombrero hat shape as well. We show that the backscattering between the outer and inner Fermi circles dominates the FP interference and significantly suppresses the dephasing effect between different transverse channels, which leads to a visible oscillation of the tunneling conductance. Specially, the visibility of the oscillating pattern can be enhanced by applying interface barriers, in contrast to that in the InAs/GaSb double quantum well. Our results provide a promising way for the implementation of the FP oscillation in the 2D electron gas.