# Conductance oscillations in Chern insulator junctions: valley-isospin dependence and Aharonov-Bohm effects

## TL;DR

This paper theoretically investigates conductance oscillations in Chern insulator junctions in quantum Hall graphene, revealing valley-isospin dependence and Aharonov-Bohm effects that influence transport properties and conductance behavior.

## Contribution

It demonstrates how valley-isospin dependence and AB effects manifest in conductance oscillations, providing insights into mesoscopic transport in Chern insulator junctions.

## Key findings

- Valley-isospin dependence causes conductance oscillations in perfect-edge graphene.
- Conductance oscillations due to AB effects are observed with longer periods for larger Chern numbers.
- Unclear conductance plateaus may result from low-visibility oscillations caused by unequal beam splitting.

## Abstract

The transport properties of Chern insulator junctions generated by bipolar junctions in quantum Hall graphene are theoretically studied in the coherent regime. Coherent transport across the junction exhibits two mesoscopic features: valley-isospin dependence of the quantum Hall conductance, and the Aharonov-Bohm (AB) effects with the interface channels. We demonstrate that the valley-isospin dependence can be measured in a graphene sample with perfect edge terminations, resulting in conductance oscillation for the smallest Chern number case. On the other hand, while conductance plateaus are found to be unclear for larger Chern numbers, the conductance exhibits an oscillatory behavior of which period is relatively longer than the valley-isospin dependent oscillation. This conductance oscillation is ascribed to the AB effect, which is implicitly created by the split metallic channels near the junction interface. We point out that a possible origin of the unclear plateaus previously speculated to be incompleteness in realistic devices is the low-visibility conductance oscillation due to unequal beam splitting.