Tunable Spin-Valley Locked Quantum Anomalous Hall Ferrovalley State in Néel Antiferromagnet Heterostructures.

The quantum anomalous Hall (QAH) effect enables dissipationless transport. However, known QAH materials rarely combine ferrovalley behavior with spin-valley locking, and Néel antiferromagnets remain largely unexplored in QAH platforms. Here, we propose a spin-valley locked QAH ferrovalley state in a MnSe/PtHgSe heterostructure. Néel-ordered MnSe induces spin-polarized bands in PtHgSe via magnetic proximity, while spin-orbit coupling lifts valley degeneracy, yielding valley-dependent gaps and a sizable QAH gap of ∼40 meV at charge neutrality. Unlike conventional QAH systems, spin-valley locking is preserved in the conduction band, producing a distinct topological phase. Chemical-potential tuning drives transitions to spin-polarized anomalous valley Hall and anomalous Hall states with opposite spin-valley responses. An out-of-plane electric field reverses the Berry curvature distribution between valleys, while the Chern number and spin-valley texture are strongly coupled to the Néel vector, establishing a tunable antiferromagnetic topological-valleytronic platform.