Engineering Room Temperature Valley States in Anisotropic van der Waals Heterostructures

Transition material dichalcogenides (TMDCs) are 2D semiconductors in the 2D material family. TMDCs have distinguishable valleys that can controlled by optically polarized lights, making them a suitable candidate for valleytronics applications[1,2]. This work presents a novel approach to modulating valley coherence in TMDCs by integrating them with anisotropic van der Waals (vdW) material α-MoO₃[3]. We demonstrate the engineering of valley coherence in α-MoO₃/WSe₂ heterostructures compared to intrinsic WSe₂[4]. We employ heterostructures which were made by stacking exfoliated α-MoO₃ on top of atmospheric pressure chemical vapour deposition (APCVD) grown WSe₂ [5,6]. Our photoluminescence measurements reveal the engineering of excitonic and trionic valley pseudospin on the Bloch sphere at room temperature. Our findings pave the way for developing tunable, room-temperature valleytronic quantum circuitry facilitated by the unique properties of α-MoO₃/WSe₂ as an in-plane anisotropic medium. This work advances our understanding of the valley degree of freedom in TMDC heterostructures and establishes a novel material platform for future valleytronic applications.