Zero-dimensionality of a scaled-down VO2 metal-insulator transition via high-resolution electrostatic gating

Abstract

An understanding of the phase transitions at the nanoscale is essential in state-of-the-art engineering1–5, instead of simply averaging the heterogeneous domains formed during phase transitions6,7. However, as materials are scaled down, the steepness of the phase transition rapidly increases8–13 and requires extremely high precision in the control method. Here, a three-terminal device, which could precisely control the phase transition electrically14–19, was applied for the first time to a scaled-down metal-insulator transition material VO2. The crossover from continuous to binary transitions with the scaled-down material was clarified, and the critical channel length was successfully elucidated via phase boundary energy. Notably, below the critical channel length, the spatial degrees of freedom degenerated, and the impact of drain voltage application disappeared in the phase transition, indicating zero-dimensionality of the VO2 channel. This zero-dimensionality could be the fundamental property in the scaled-down phase transition and have a significant impact on various fields that need nanoscale engineering.