HOLE BOUND-STATES IN THE DEFORMATION FIELD OF SCREW DISLOCATIONS IN CUBIC SEMICONDUCTORS

For the spherically averaged Hamiltonian approximation an accurate non variational calculation is reported of the energies of the one-dimensi onal bands split off from the edge of the valence band by the shear st rain fields of screw dislocations in various cubic semiconductors. The calculation gives significantly greater binding energies for holes th an previous variational calculations and also a different order of the first two levels when the ratio of light- and heavy-hole masses is le ss than 0.19. The calculation was performed on the basis of the effect ive-mass and deformation-potential approximations. This approach is ju stified because the resulting binding energies are much smaller than t he energy gaps. The results may be used for the interpretation of vari ous dislocation-related phenomena such as luminescence, absorption, mi crowave conductivity, and combined resonance (a kind of electric-dipol e spin resonance).