2026/07/20 by Jackson Kuklin, Ning Mao, Milan Mandigo-Stoba +9
#cond-mat.mes-hall
Electronic orbital character plays a central role in determining electronic correlations, spin-orbit coupling, dimensionality, and ultimately the quantum phases of condensed-matter systems. Two-dimensional moiré materials have emerged as highly tunable platforms for exploring correlated phenomena, but the role of orbital degrees of freedom remains largely unexplored. Here, we identify twisted monolayer/bilayer WSe2 as a platform in which displacement-field tuning enables moiré physics to be realized in both the K and Γ valleys. The distinct orbital characters of these valleys give rise to contrasting correlated phases at moiré filling factors ν=1 and ν=1/3. At ν=1, the K-valley state is a weak insulator, consistent with an antiferromagnetic state near a van Hove singularity in the intermediate-coupling regime, similar to that observed in twisted bilayer WSe2. In contrast, the Γ-valley state exhibits a pronounced Pomeranchuk effect, consistent with proximity to a Mott transition. At ν=1/3, the K valley hosts a robust generalized Wigner crystal, whereas the Γ-valley state lies near the crystallization boundary and again exhibits a Pomeranchuk effect, with localization enhanced by increasing temperature or magnetic field. Our work highlights the importance of orbital character in defining quantum phases in moiré systems, and identify the Γ valley as a promising platform for exploring correlated phenomena near quantum phase transitions, where competing phases and enhanced fluctuations may give rise to unconventional phases.