The dispersion law of holes which were bound to a screw dislocation in a cubic semiconductor was calculated on the basis of deformation potential theory; taking into account the threefold degeneracy of the valence band maximum in a perfect crystal. The lowest dislocation band (with a corresponding azimuthal quantum number of m = 0) was slightly affected by anisotropy of the effective mass. Only the change in the effective mass was observed. States with azimuthal number m ≠ 0 were considerably more affected by an anisotropy of the effective mass. Mixing of longitudinal and transverse motions (with respect to the dislocation line direction) took place and terms which were linear in k|| appeared in the dispersion law. The optical transitions which were associated with these states were intense for light polarization which was transverse with respect to the dislocation line, and could cause some circular dichroism in the absorption. The long-wave edge of the dislocation absorption was generally formed by transitions from the deepest band, m = 0, and was polarized along the Burgers vector.

Bound Hole States in Direct-Gap Semiconductors with Screw Dislocations. M.A.Razumova, V.N.Khotyaintsev: Physica Status Solidi B, 1995, 188[2], 751-60