Quantum Anomalous Hall Effect in 2D Organic Topological Insulators

TL;DR

This paper predicts a new class of 2D organic topological insulators capable of exhibiting the quantum anomalous Hall effect, using first-principles calculations to demonstrate their topological properties without external magnetic fields.

Contribution

It introduces a novel design of organic materials for QAHE based on triphenyl-transition-metal compounds, expanding the material scope beyond inorganic systems.

Findings

Presence of nonzero Chern number in designed OTIs

Existence of gapless chiral edge states within the Dirac gap

Potential realization of QAHE in organic materials

Abstract

Quantum anomalous Hall effect (QAHE) is a fundamental transport phenomenon in the field of condensed-matter physics. Without external magnetic field, spontaneous magnetization combined with spin-orbit coupling give rise to a quantized Hall conductivity. So far, a number of theoretical proposals have been made to realize the QAHE, but all based on inorganic materials. Here, using first-principles calculations, we predict a family of 2D organic topological insulators (OTIs) for realizing the QAHE. Designed by assembling molecular building blocks of triphenyl-transition-metal compounds into a hexagonal lattice, this new classes of organic materials are shown to have a nonzero Chern number and exhibit a gapless chiral edge state within the Dirac gap.