Temperature dependence of the electron spin g factor in CdTe and InP

摘要

Temperature dependence of the electron spin g factors in bulk CdTe and InP is calculated and compared with experiment. It is assumed that the only modification of the band structure related to temperature is a' dilatation change in the fundamental energy gap. The dilatation changes of fundamental gaps are calculated for both materials using available experimental data. Computations of the.band structures in the presence of a magnetic field are carried out employing five-level P·p model appropriate for medium-gap semiconductors. In particular, the model takes into account spin splitting due to bulk inversion asymmetry (BIA) of the materials. The resulting theoretical effective masses and g factors increase with electron energy due to band nonparabolicity. Average g values are calculated by summing over populated Landau and spin levels properly accounting for the thermal distribution of electrons in the band. It is shown that the spin splitting due to BIA in the presence of a magnetic field gives observable contributions to g values. Our calculations are in good agreement with experiments in the temperature range of OK to 300K for CdTe and 0K to 180K for InP. The temperature dependence of g is stronger in CdTe than in InP due to different signs of band-edge g values in the two materials. Good agreement between the theory and experiments strongly indicates that the temperature dependence of spin g factors is correctly explained. In addition, we discuss formulas for the energy dependence of spin g factor due to band nonparabolicity, which are liable to misinterpretation.