Acoustic Phonon-Assisted Resonant Tunneling via Single Impurities

TL;DR

This paper investigates phonon-assisted resonant tunneling through impurities in a GaAs/AlGaAs heterostructure, revealing individual donor contributions, phonon effects, and local density of states fluctuations at very low temperatures.

Contribution

It provides detailed experimental analysis and modeling of phonon-assisted tunneling via single impurities, a novel insight into impurity-related quantum transport mechanisms.

Findings

Resolved individual donor contributions in tunneling data

Identified phonon assistance in the tunneling process

Observed fluctuations in local density of states and Fermi edge singularities

Abstract

We perform the investigations of the resonant tunneling via impurities embedded in the AlAs barrier of a single GaAs/AlGaAs heterostructure. In the $I(V)$ characteristics measured at 30mK, the contribution of individual donors is resolved and the fingerprints of phonon assistance in the tunneling process are seen. The latter is confirmed by detailed analysis of the tunneling rates and the modeling of the resonant tunneling contribution to the current. Moreover, fluctuations of the local structure of the DOS (LDOS) and Fermi edge singularities are observed.