Ferroelectric control of the Mott insulator–topological metal transition

Correlated and topological phases often coexist or compete in van der Waals materials, yet achieving an electrically switchable and reversible conversion between them remains a substantial challenge. Such control is crucial for understanding their interplay and enabling nonvolatile, low-power topological electronics. Here, we propose and demonstrate a polarization-controlled route to switch between Mott insulator and topological metal in ferroelectric-Mott heterostructures. In α-In ₂ Se ₃ /1T-NbSe ₂ , polarization reversal modulates interlayer coupling through out-of-plane orbital alignment. Downward polarization stabilizes Mott-insulating states with type-I band alignment, whereas upward polarization enhances interfacial hybridization, forms interlayer covalent-like quasi-bonding, and drives Γ-point band inversions. The resulting spin-split hybridized valleys penetrate the valence band, inducing a nontrivial topological state with intrinsic anomalous Hall conductivity of ∼10 ²  siemens per centimeter. The comparison with α-In ₂ Se ₃ /1T-TaSe ₂ and α-In ₂ Se ₃ /1T-TaS ₂ further identifies Γ-centered valleys and out-of-plane p z -orbital coupling as key ingredients for polarization-switchable topology, providing a general design framework for electrically programmable correlated-topological integration in two-dimensional heterostructures.