Study of Band Structure of Intermetallic Compounds by Pressure Experiments

Abstract

The effect of hydrostaticpressure on the transport properties of n‐type GaSb,InP,GaP, and p‐type PbTe was measured to study their band structure. (1) The Seebeck coefficient, Hall coefficient, and resistance of three n‐GaSb samples were measured as a function of hydrostaticpressure up to 17 000 atm between 200° and 400°K. The Seebeck coefficient α increased with pressure and approached a constant value at about 10 000 atm. The saturation value of α does not follow the simple 3 2 lnT relation for any of the samples; e.g., for a sample with RH (77°K) ≈95 coul−1 cm3, the saturation value of α decreases with temperature. The contribution due to the phonon‐drag effect has been considered as a possible explanation for this phenomenon. (2) The conductivity of p‐PbTe increased almost exponentially with pressure both at 300° and 194°K; the Hall coefficient at 300°K decreased by about 5% at 8000 atm, while the conductivity increased by 55% at this pressure. (3) The resistance of n‐InP samples increased with pressure; the pressure coefficient was found to be bigger for samples with higher impurity contents. (4) The resistance of an n‐GaP sample decreased by about 3% at 10 000 atm.