Time-dependent transport in Graphene Mach-Zender Interferometers

TL;DR

This paper investigates time-dependent electron transport in graphene Mach-Zehnder interferometers, revealing dynamical effects and novel phenomena, which advance understanding of quantum interference in graphene-based nanodevices.

Contribution

It introduces a detailed simulation of time-dependent transport in graphene MZIs, including new effects from valley beam splitters and insights into device operability.

Findings

Observation of Aharonov-Bohm oscillations and phase averaging in QPC-based MZIs

Discovery of unexpected phenomena at Valley Beam Splitters due to edge channel intersections

Identification of feasible regimes for single-particle graphene interferometry

Abstract

Graphene nanoribbons provide an ideal platform for electronic interferometry in the Integer Quantum Hall regime. Here, we solve the time-dependent four-component Schroedinger equation for single carriers in graphene and expose several dynamical effects of the carrier localization on their transport characteristics in pn junctions. We simulate two kinds of Mach-Zender Interferometers (MZI). The first is based on Quantum Point Contacts and is similar to traditional GaAs/AlGaAs interferometers. As expected, we observe Aharonov-Bohm oscillations and phase averaging. The second is based on Valley Beam Splitters, where we observe unexpected phenomena due to the intersection of the Edge Channels that constitute the MZI. Our results provide further insights into the behavior of graphene interferometers. Additionally, they highlight the operative regime of such nanodevices for feasible single-particle implementations.