Aharonov-Bohm electron interferometer in the integer quantum Hall regime

TL;DR

This paper reports on experiments with a quantum electron interferometer in the quantum Hall regime, demonstrating Aharonov-Bohm oscillations and analyzing the dependence of the interference area on gate voltages using electrostatic models.

Contribution

It provides experimental measurements of the interference area dependence on gate voltages and confirms the Aharonov-Bohm quantization without significant corrections, supported by electrostatic modeling.

Findings

Periodic Aharonov-Bohm oscillations observed in resistance.

Interference area remains consistent with quantization conditions.

Electrostatic models successfully describe the electron density profile.

Abstract

We report experiments on a quantum electron interferometer fabricated from high mobility, low density GaAs/AlGaAs heterostructure material. In this device, a nearly circular electron island is defined by four front gates deposited in etched trenches. The island is separated from the 2D electron bulk by two nearly open constrictions. In the quantum Hall regime, two counterpropagating edge channels are coupled by tunneling in the constrictions, thus forming a closed electron interference path.For several fixed front gate voltages, we observe periodic Aharonov-Bohm interference oscillations in four-terminal resistance as a function of the enclosed flux. The oscillation period DeltaB gives the area of the interference path S via quantization condition S=h/eDeltaB. We experimentally determine the dependence of S on the front gate voltage, and find that the Aharonov-Bohm quantization condition does not require significant corrections due to the confining potential. These results can be interpreted as a constant integrated compressibility of the island with respect to the front gates. We also analyze experimental results using two classical electrostatics models: one modeling the 2D electron density due to depletion from an etch trench, and another modeling the gate voltage dependence of the electron density profile in the island.