Sliding-ferroelectric order imprinted onto excitonic and valley responses in van der Waals heterostructures

Abstract

Ferroelectricity driven by interlayer sliding provides a distinct route to nonvolatile control in van der Waals (vdW) heterostructures, yet resolving stacking-dependent ferroelectric states and their local interfacial consequences remains challenging. Here, we report that bilayer 1T′-ReS2 (2L-ReS2) hosts distinct AB and BA stacking configurations associated with opposite sliding-ferroelectric polarizations, identified through symmetry-sensitive structural and optical characterization. When coupled to monolayer MoSe2, these stacking-associated ferroelectric states produce pronounced redistribution between neutral and charged exciton emission, providing a sensitive optical fingerprint of the local interfacial electrostatic environment. Their distinct signatures further extend to valley-resolved magneto-optical responses, including domain-dependent circular-polarization evolution and effective charged-exciton g-factors of −3.8 ± 0.09 and −6.7 ± 0.18. First-principles calculations based on the experimentally identified AB and BA configurations reveal stacking-selective interfacial charge redistribution and corresponding shifts of the MoSe2-derived band edges, providing a microscopic basis for the observed excitonic reconstruction. These results establish sliding-ferroelectric order as a buried yet optically readable interfacial degree of freedom and identify stacking registry as a nonvolatile handle for controlling excitonic and valley responses in vdW heterostructures.