Photoinduced High-Chern-Number Quantum Anomalous Hall Effect from Higher-Order Topological Insulators

TL;DR

This paper proposes a dynamic method to realize high-Chern-number quantum anomalous Hall phases in periodically driven higher-order topological insulators, identifying monolayer graphdiyne as a promising material candidate.

Contribution

It introduces a novel approach using Floquet theory to achieve tunable high-Chern-number QAH phases in HOTIs, supported by first-principles calculations.

Findings

High-Chern-number QAH phases up to four are achievable.

Monolayer graphdiyne is identified as an ideal candidate.

The approach enables exploration of exotic topological states out of equilibrium.

Abstract

Quantum anomalous Hall (QAH) insulators with high Chern number host multiple dissipationless chiral edge channels, which are of fundamental interest and promising for applications in spintronics and quantum computing. However, only a limited number of high-Chern-number QAH insulators have been reported to date. Here, we propose a dynamic approach for achieving high-Chern-number QAH phases in periodically driven two-dimensional higher-order topological insulators (HOTIs).In particular, we consider two representative kinds of HOTIs which are characterized by a quantized quadruple moment and the second Stiefel-Whitney number, respectively. Using the Floquet formalism for periodically driven systems, we demonstrate that QAH insulators with tunable Chern number up to four can be achieved. Moreover, we show by first-principles calculations that the monolayer graphdiyne, a realistic HOTI, is an ideal material candidate. Our work not only establishes a strategy for designing high-Chern-number QAH insulators in periodically driven HOTIs, but also provides a powerful approach to investigate exotic topological states in nonequilibrium cases.