Electron tunneling in chaotic InAs/GaAs quantum ring

TL;DR

This paper investigates electron tunneling in chaotic InAs/GaAs quantum rings, analyzing how shape asymmetry affects energy spectra and tunneling, and explaining chaos-assisted tunneling through inter-band interactions and level anti-crossings.

Contribution

It introduces a detailed analysis of electron tunneling in asymmetric quantum rings and explains chaos-assisted tunneling via inter-band interactions and anti-crossings.

Findings

Spectrum shows quasi-doublets for weak symmetry violation.

Tunneling depends on quantum ring eccentricity.

Chaos-assisted tunneling explained by inter-band level anti-crossings.

Abstract

Two dimensional InAs/GaAs quantum ring (QR) is considered using the effective potential approach. The symmetry of QR shape is violated as it is in the well-known Bohigas annular billiard. We calculate energy spectrum and studied the spatial localization of a single electron in such QR. For weak violation of the QR shape symmetry, the spectrum is presented as a set of quasi-doublets. Tunneling between quasi-doublet states is studied by the dependence on energy of the states. The dependence is changed with variation of the QR geometry that is related to the eccentricity of the QR. An interpretation of the experimental result obtained in [1] is proposed. We show that the "chaos-assisted tunneling" effect found in this paper can be explained by inter-band interactions occurred by anti-crossing of the levels with different "radial" quantum numbers.