Nonvolatile metal–semiconductor transition of a single valley in two-dimensional ferrovalley/ferroelectric van der Waals heterostructures

In valleytronics, achieving nonvolatile control of valley properties remains a significant challenge. In this study, we construct TaNF/Sc₂CO₂ van der Waals (vdW) heterostructures and investigate their properties using first-principles density functional theory. We demonstrate that by controlling the ferroelectric polarization direction of Sc₂CO₂, a reversible and nonvolatile transition of a single valley in TaNF from a semiconductor to a metal can be achieved. The heterostructures also exhibit high Curie temperatures, underscoring their potential for practical applications. Furthermore, quantum transport simulations based on two-probe nanodevices confirm that the metal-semiconductor transition is feasible for nonvolatile devices. These findings establish a foundation for ferroelectric control of valleys and present TaNF/Sc₂CO₂ heterostructures as promising candidates for future spintronic and valleytronic devices.