2026, Nonvolatile Electrical Programming of Valley Pseudospins in a Ferroelectric van der Waals Heterostructure, Advanced Functional Materials.

2026, Nonvolatile Electrical Programming of Valley Pseudospins in a Ferroelectric van der Waals Heterostructure, Advanced Functional Materials.

Abstract:

Valley pseudospin, the third quantum degree of freedom for electrons in two-dimensional crystals after charge and spin, exhibits two distinguishable states (K and −K) serves as a versatile platform for information encoding, manipulation, and low-power quantum technologies. However, most existing approaches rely on continuous external fields to transiently induce valley polarization, without stable K/−K occupation imbalance, fundamentally preventing nonvolatile valley-based memory. Here, we demonstrate nonvolatile and electrically programmable control of valley pseudospins in a van der Waals heterostructure composed of monolayer MoSe₂ and ferroelectric CuInP₂S₆ (CIPS). By integrating a gold micropillar electrode array with an electromechanical modulation scheme, we introduce localized strain gradients into the MoSe₂/CIPS heterostructure, generating flexoelectric fields that drive Cu⁺ redistribution and enable robust, energy-efficient control of excitonic properties. Magneto-optical spectroscopy reveals that ferroelectric polarization-induced interfacial fields enable reversible switching between spin-allowed bright and spin-forbidden dark trions, accompanied by a reversible Landé g-factor tuning from −4.7 to −7.8. Under an external magnetic field, electrically driven valley polarization reaches 35.7%, exhibiting high contrast and long-term retention. Furthermore, ASCII-encoded valley polarization states demonstrate reliable nonvolatile information storage. This work establishes a versatile ferroelectric platform for reconfigurable valleytronic memory and programmable quantum photonics, paving the way toward scalable and energy-efficient quantum information technologies.

Keywords: MoSe₂, CuInP₂S₆, ferroelectric, valleytronic, valley pseudospin, nonvolatile.

Link: http://doi.org/10.1002/adfm.202528029

Adv Funct Materials - 2026 - Hou - Nonvolatile Electrical Programming of Valley Pseudospins in a Ferroelectric Van Der.pdf