Structure and phase diagram determinations for novel materials under high-pressure conditions using synchrotron X-ray techniques

The structural evolution of material under pressure is the long-term active research subject, which in fact strongly depends on the development of corresponding high pressure and synchrotron technologies. Many interesting results, such as syntheses or transition to high Tc superconductivity under high pressure conditions, were reported in last decade, but the responsible structures are not well studied at correct P-T conditions and mechanisms are far away from fully understood. In this presentation, several selected systems were in situ studied under high pressure using synchrotron x-ray diffraction (XRD) techniques in diamond anvil cell (DAC) at ambient temperature and low temperature conditions, will be introduced. Selected cases, including pure element cases of Ti and Sc, typical metal hydrides, and oxides systems such as La-Ni-O, Ba-K-Bi-O, etc., would be discussed based on the their XRD results and the corresponding first principle calculations, and the updated phase diagrams at low-temperature and high-pressure domains.