Graphene-Based Quantum Hall Interferometer with Self-Aligned Side Gates
Lingfei Zhao, Ethan G. Arnault, Trevyn F. Q. Larson, Zubair Iftikhar, Andrew Seredinski, Tate Fleming, Kenji Watanabe, Takashi Taniguchi, François Amet, Gleb Finkelstein
Abstract
The vanishing band gap of graphene has long presented challenges for making high-quality quantum point contacts (QPCs)─the partially transparent p-n interfaces introduced by conventional split gates tend to short circuit the QPCs. This complication has hindered the fabrication of graphene quantum Hall Fabry-Pérot interferometers, until recent advances have allowed split-gate QPCs to operate utilizing the highly resistive ν = 0 state. Here, we present a simple recipe to fabricate QPCs by etching a narrow trench in the graphene sheet to separate the conducting channel from self-aligned graphene side gates. We demonstrate operation of the individual QPCs in the quantum Hall regime and further utilize these QPCs to create and study a quantum Hall interferometer.