Disordered matter under extreme conditions: X-ray diffraction, electron spectroscopy and electroresistance measurements

In the last decade, we have developed a set of experimental techniques for in-house X-ray diffraction measurements under high-temperature (up to about 2300 K) and high-pressure (up to 10 GPa and 1500 K, up to 100 GPa and 700 K) conditions, electron energy-loss and Auger measurements for surface electronic structure measurements at high-temperature (up to about 1800 K), and electrical resistance measurements covering both low-temperatures (2 K) and high-temperatures/high-pressures (1500 K, 7 GPa) conditions. In this paper we discuss some important technical features and possibilities of these new equipments and present novel data collected for phase transitions and structural modifications occurring in liquid and solid systems. In particular, we present new results about phase transitions and undercooling of bismuth under pressure, extreme undercooling and metastable states in gallium films, and surface phase transitions of Si at high-temperatures. The relevance of these experiments to the exploitation of the potential of equipments available at synchrotron radiation facilities is emphasized.