Engineering topologically protected zero-dimensional interface end states in antiferromagnetic heterojunction graphene nanoflakes

TL;DR

This paper demonstrates the theoretical design of a heterojunction of antiferromagnetic graphene nanoflakes that hosts topologically protected zero-dimensional interface states, which are robust and controllable.

Contribution

It introduces a novel method to engineer topologically protected zero-dimensional states at interfaces in antiferromagnetic graphene heterojunctions using the modified Kane-Mele model.

Findings

Zero-dimensional in-gap states are induced at the interface.

The in-gap states are robust against various disorders.

The states can be precisely controlled in position and number.

Abstract

We investigate the energy band structure and energy levels of a heterojunction composed of two antiferromagnetic graphene nanoflakes with opposite in-plane antiferromagnetic orderings, in which the modified Kane-Mele model is employed. Before forming an antiferromagnetic graphene heterojunction, the energy gap of helical edge states in each isolated graphene nanoflake are opened by the antiferromagnetic ordering and there is no the in-gap corner state. We find that when two opposite antiferromagnetic graphenes are coupled to form a heterojunction nanoflake, topologically protected zero-dimensional in-gap states can be induced. In addition, we demonstrate that the in-gap states locate at the end of the interface and are robust against magnetic disorder, Anderson disorder, and interfacial magnetic defects. The position and number of the in-gap interface end states in the heterojunction sample can be precise quantum controlled.