Current partition at zero-line intersection of quantum anomalous Hall topologies

TL;DR

This paper investigates zero-line modes at the interface of quantum anomalous Hall topologies, revealing their chiral, unidirectional conduction properties, and how current partitioning can be controlled by magnetic and geometric parameters.

Contribution

It provides a detailed analysis of zero-line mode behavior at quantum anomalous Hall interfaces, including their robustness and tunability, which advances understanding of topological edge state manipulation.

Findings

Zero-line modes are chiral and unilaterally conductive.

Current partitioning is simplified and robust against Fermi energy shifts.

Partition can be tuned by magnetization strength and zero-line angles.

Abstract

At the interface between two-dimensional materials with different topologies, topologically protected one-dimensional states (also named as zero-line modes) arise. Here, we focus on the quantum anomalous Hall effect based zero-line modes formed at the interface between regimes with different Chern numbers. We find that, these zero-line modes are chiral and unilaterally conductive due to the breaking of time-reversal invariance. For a beam splitter consisting of two intersecting zero lines, the chirality ensures that current can only be injected from two of the four terminals. Our numerical results further show that, in the absence of contact resistance, the (anti-)clockwise partitions of currents from these two terminals are the same owing to the current conservation, which effectively simplifies the partition laws. We find that the partition is robust against relative shift of Fermi energy, but can be effectively adjusted by tuning the relative magnetization strengths at different regimes or relative angles between zero lines.