Intriguing heterophase domain patterns in correlated electron material via tip force engineering

Abstract

Vanadium dioxide (VO2) is a compelling correlated electron material in advanced electronics and fundamental research, for its fascinating metal-insulator transition (MIT) and tunability by external stimuli. However, despite of its well-known strain sensitivity, the potential of local strain control of the heterophase domain patterning in VO2 remains largely unexamined. Here, we report that intriguing heterophase domain patterns can be mechanically created in VO2 platelets via tip pressing forces. Based on tip-domain and domain-domain interactions, letter-shaped patterns (e.g., ‘I’, ‘V’, ‘N’, ‘W’, ‘Y’, etc.) and geometry-shaped patterns (e.g., wedge, parallelogram, triangle, diamond, etc.) can be readily obtained. Moreover, the global and local electronic transport behaviors of VO2 platelets are sensitive to the induced heterophase domain patterns, based on which, device concepts like force-gate-transistors and anti-crosstalk devices are demoed. The feasible tip force control on the MIT heterophase structures of VO2 also paves a way to explore the phase transition physics of materials with a strong first-order feature.