Pressure spectroscopy of impurity states and band structure of bismuth telluride

The pressure and temperature dependences of the resistivity, the Hall effect and the Shubnikov-de Haas effect were investigated in p-Bi 2 Te 3 , p-Bi 2 Te 3 (Ge) and p-In x Bi 2-x Te 3 for pressures up to 12 kbar and temperatures in the range 1.5 <T<300 K. In samples of p-In x Bi 2-x Te 3 with x>0.1 an increase of the upper hole band concentration of carriers under pressure and an increase of the resistivity and of the Hall coefficient R x at T<10 K were observed. The results were interpreted as pointing to the existence of impurity states in In-doped samples.