Electrical Properties of Tellurium under Hydrostatic Pressure. I. Effects on Its Effective Mass and Energy Gap

Conductivity and Hall coefficient have been measured in undoped and Sb‐doped tellurium at 77 and 273 K under hydrostatic pressure up to 7000 bar. It is found that the hole mobility increases with pressure and that the sample with its c‐axis perpendicular to the current direction shows a more rapid mobility increase than the parallel one. The mobility increase under pressure in undoped tellurium is interpreted as resulting from the decrease in the hole effective mass under pressure, and the pressure coefficients of the hole effective mass are derived from the experimental results. The pressure coefficients of the energy gap including the second order one are also obtained from the precise measurement of the pressure dependence of the Hall coefficient of undoped tellurium at 273 K, where it is intrinsic.