Bi₄X₄(X= Br, I)-Based High-Temperature Quantum Spin Hall Physics

The manifestation of quantum phenomena at room temperatures is a major challenge but also a major goal in physics, and this is particularly true for the quantum spin Hall effect. Here we report the theoretical demonstration of high-temperature quantum spin Hall systems based on Bi₄X₄ (X= Br, I), a rare higher-order topological insulators identified recently. We further investigate their behavior under external electric field. We also comment on the key experimental studies.