Fabry-P\'erot interference in a triple-gated quantum point contact

TL;DR

This paper reports on the observation of Fabry-Pérot interference patterns in a triple-gated GaAs quantum point contact, revealing detailed insights into quantum conductance and oscillations using a phenomenological model.

Contribution

It introduces a triple-gated design that enhances lateral confinement and explains oscillatory behavior with a new phenomenological model.

Findings

Observation of well-defined quantized conductance

Identification of Fabry-Pérot-type oscillations

Correlation between oscillations and conductance anomalies

Abstract

We demonstrated that a triple-gated GaAs quantum point contact, which has an additional surface gate between a pair of split gates to strengthen the lateral confinement, produces the well-defined quantized conductance and Fabry-P\'erot-type (FP-type) oscillations on it even using a relatively low mobility wafer. A one-dimensional phenomenological model potential was developed to explain the oscillatory behavior. By combining the model calculations and dc bias spectroscopy, we obtained detailed information about the energy scales of the oscillatory structures. The relationships between the FP-type oscillations and the anomaly below the first plateau will be addressed.