Aharonov-Bohm oscillations of four-probe resistance in topological quantum rings in silicene and bilayer graphene

TL;DR

This paper explores Aharonov-Bohm oscillations in four-probe resistance measurements in topological quantum rings made of silicene and bilayer graphene, highlighting the role of topologically protected chiral currents and specific electric field configurations.

Contribution

It introduces a novel electric field profile forming a crossed ring in silicene and bilayer graphene, enabling observation of conductance oscillations without backscattering.

Findings

Conductance matrix elements oscillate with magnetic field.

Large visibility of resistance oscillations under specific conditions.

Chiral currents are confined and flow without backscattering.

Abstract

We consider observation of Aharonov-Bohm oscillations in clean systems based on the flow of topologically protected currents in silicene and bilayer graphene. The chiral channels in these materials are defined by the flips of the vertical electric field. The line of the flip confines chiral currents flowing along it in the direction determined by the valley. We present an electric field profile that forms a crossed ring to which four terminals can be attached, and find that the conductance matrix elements oscillate in the perpendicular magnetic field in spite of the absence of backscattering. We propose a four-probe resistance measurement setup, and demonstrate that the resistance oscillations have large visibility provided that the system is prepared in such a way that a direct transfer of the chiral carriers between the current probes is forbidden.