Determination of the band structure of semimagnetic semiconductors from thermoelectric power studies

Abstract

Thermoelectric power and Hall effect were measured for samples with and , with carrier concentration over a temperature range T = 4.2-300 K. The analysis of the experimental data based on a two-valence-band model was performed. The theoretical description of the light holes of the L band is based on the Dimmock model. For heavy holes from the band the parabolic dispersion relation was assumed. Our analysis indicates that with increasing Mn content the energy gap increases: , whereas the energy separation between the bands of light and heavy holes decreases: . We also observe an increase of the effective mass of heavy holes from for samples with to for x = 0.12.