Identifying the Collective Length in VO₂ Metal–Insulator Transitions

In a study, VO₂ heterostructures were epitaxially grown on the TiO ₂. Both VO₂ and TiO₂ had the tetragonal structure with the small lattice mismatch plane and the VO₂ thin film with an atomically flat surface could grow up to around 15 nm thickness without lattice relaxation on the TiO₂ substrate. The metal–insulator transition in VO ₂ occurred between the insulating phase at low temperature and the metallic phase at high temperature.