Radio-frequency reflectometry on large gated 2-dimensional systems

TL;DR

This paper demonstrates radio-frequency reflectometry as an effective technique for sensitive, high-bandwidth electrical resistance measurements of large gated 2D systems at millikelvin temperatures, enabling detailed mapping of Landau levels.

Contribution

It introduces a novel application of RF reflectometry to large gated 2D hole systems, providing a simple model and experimental validation for high-resolution resistance measurements.

Findings

Successful implementation of RF reflectometry on 2D hole systems

Ability to map Landau level evolution with high precision

Model explains qualitative behavior of the measurements

Abstract

We have embedded an AlGaAs/GaAs based, gated 2D hole system (2DHS) into an impedance transformer $LC$ circuit, and show that by using radio-frequency reflectometry it is possible to perform sensitive, large bandwidth, electrical resistance measurements of 2D systems at mK temperatures. We construct a simple lumped element model where the gated 2DHS is described as a resistive transmission line. The model gives a qualitative understanding of the experimental results. As an example, we use our method to map out the Landau level evolution in a 2DHS as a function of magnetic field and gate voltage.