Electrical transport and high pressure studies on bulk Ge<SUB>20</SUB>Te<SUB>80</SUB> glass

The electrical resistivity of bulk Ge<SUB>20</SUB>Te<SUB>80</SUB> has been measured as a function of pressure and temperature. At 5 GPa, an amorphous semiconductor-to-crystalline metal transition has been observed. The sample recovered from the high pressure cell, after the application of 7 GPa, has a face-centred cubic structure with a lattice constant of 6·42 A. In crystalline sample, the semiconductor-to-metal transition occurs at 7 GPa. The thermoelectric power has also been measured for glassy samples in the temperature range 300-240 K