Floquet valley-polarized quantum anomalous Hall state in nonmagnetic heterobilayers

The valley-polarized quantum anomalous Hall (VQAH) state, which forwards a strategy for combining valleytronics and spintronics with nontrivial topology, attracts intensive interest in condensed-matter physics. So far, the explored VQAH states have still been limited to magnetic systems. Here, using low-energy effective model Floquet theorem, we propose different mechanism realize state nonmagnetic heterobilayers under light irradiation. We then this proposal via first-principles calculations transition metal dichalcogenide heterobilayers, initially possess time-reversal invariant valley spin (VQSH) state. By irradiating circularly polarized light, VQSH can evolve into behaving as an optically switchable topological spin-valley filter. These findings not only offer rational scheme without orders, but also pave fascinating path designing spintronic valleytronic devices.