Metal-Insulator Transition of Single-Crystal V2O3 through van der Waals Interface Engineering

Strongly correlated electron materials harbor interestingmaterialsphysics, such as high-T (c) superconductivity,colossal magnetoresistance, and metal-insulator transition.These physical properties can be greatly influenced by the dimensionalityand geometry of the hosting materials and their interaction strengthswith underlying substrates. In a classic strongly correlated oxidevanadium sesquioxide (V2O3), the coexistenceof a metal-insulator and paramagnetic-antiferromagnetic transitionsat similar to 150 K makes this material an excellent platform for exploringbasic physics and developing future devices. So far, most studieshave been focused on epitaxial thin films in which the strongly coupledsubstrate has a pronounced effect on V2O3, leadingto the observations of intriguing phenomena and physics. In this work,we unveil the kinetics of a metal-insulator transition of V2O3 single-crystal sheets at nano and micro scales.We show the presence of triangle-like alternating metal/insulatorphase patterns during phase transition, which is drastically differentfrom the epitaxial film. The observation of single-stage metal-insulatortransition in V2O3/graphene compared to themultistage in V2O3/SiO2 evidencethe importance of sheet-substrate coupling. Harnessing thefreestanding form of the V2O3 sheet, we showthat the phase transition of V2O3 sheet cangenerate a large dynamic strain to monolayer MoS2 and tuneits optical property based on the MoS2/V2O3 hybrid structure. The demonstration of the capability intuning phase transition kinetics and phase patterns using designedhybrid structure of varied sheet-substrate coupling strengthssuggests an effective knob in the design and operation of emergingMott devices.