Three-dimensional visualization of metal-insulator transition of VO2 by ptychographic Bragg coherent diffraction imaging

The metal-insulator transition (MIT) of Vanadium dioxide (VO2) has attracted great attention due to its wide potential applications, e.g., smart windows, memory devices, and optical switching devices, based on a relatively low critical temperature and large changes in resistivity. One key parameter for the device performance is the strain-involved structural evolution during phase transition, which is still lacking. In our previous microbeam X-ray diffraction study, we confirmed the coexistence of the M1 and M2 phases caused by tensile strain. Here, we propose an in-situ temperature-dependent diffraction imaging of VO2 microcrystals to investigate the MIT and its intermediate phases to improve our knowledge of the MIT for development of high performance nano-devices with specific functionalities by controlling the morphology of twin VO2 nanocrystals.