High-temperature quantum anomalous Hall effect in honeycomb bilayer consisting of Au atoms and single-vacancy graphene.

Yan Han,Guang-Hou Wang,Jian-Guo Wan,Gui-Xian Ge,Feng-Qi Song

doi:10.1038/srep16843

Abstract

The quantum anomalous Hall effect (QAHE) is predicted to be realized at high temperature in a honeycomb bilayer consisting of Au atoms and single-vacancy graphene (Au2-SVG) based on the first-principles calculations. We demonstrate that the ferromagnetic state in the Au2-SVG can be maintained up to 380 K. The combination of spatial inversion symmetry and the strong SOC introduced by the Au atoms causes a topologically nontrivial band gap as large as 36 meV and a QAHE state with Chern number C = −2. The analysis of the binding energy proved that the honeycomb bilayer is stable and feasible to be fabricated in experiment. The QAHEs in Ta2-SVG and other TM2-SVGs are also discussed.

Highlights

If time-reversal and spatial inversion symmetries simultaneously exist in the crystal[13]
In 1988, Haldane proposed a toy model to realize QAHE1. In this model the ions were arranged in a planar, honeycomb lattice to keep the spatial inversion symmetry and a periodic local magnetic-flux density normal to the 2D plane was added to the lattice to break the time-reversal invariance
There is a drawback of introducing SVs into the graphene, i.e. original spatial inversion symmetry of the graphene may be broken by the SVs

Summary

Introduction

If time-reversal and spatial inversion symmetries simultaneously exist in the crystal[13]. The high-temperature QAHE is proposed to be realized in a honeycomb bilayer consisting of Au atoms and SV graphene (Au2-SVG) based on first-principles calculations.

Results

Conclusion