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

Vanadium dioxide (VO ₂) 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 VO ₂ remains largely unexamined. Here, we report that intriguing heterophase domain patterns can be mechanically created in VO ₂ 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 VO ₂ 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 VO ₂ also paves a way to explore the phase transition physics of materials with a strong first-order feature.