Abstract
General expressions for the parabolic effective masses and factors are obtained in terms of seven undetermined parameters for a six-band model at the point of the NaCl lattice. The spin-orbit mixing of bands is treated explicitly with the result that both longitudinal and transverse components of the momentum are coupled between bands with symmetry and opposite parity. The six bands of interest are treated in the free-electron and tight-binding limits. The simplified expressions in the tight-binding limit, which approximate PbS, give spherical and nondegenerate valence- and conduction-band parameters. In this limit, the bands at are similar in detail to certain of the bands at in germanium and the III-V compounds. Expressions, valid over an extended range of k, are also obtained for the nonparabolic effective masses and factors. The signs of the factors are treated in detail in order to resolve the differences which have appeared in the literature.
- Received 11 April 1966
DOI:https://doi.org/10.1103/PhysRev.151.581
©1966 American Physical Society