Effects of uniaxial stress on hole subbands in semiconductor quantum wells. II. Numerical results

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Abstract
Numerical results on valence-subband structures and the hole effective masses are presented for a quantum well under uniaxial stress. For each eigenenergy, the corresponding components of the eigenfunction are calculated. By examining the relative magnitudes of the components of the eigenfunction, we are able to distinguish whether the eigenfunction is heavy-hole-like or light-hole-like, when k is near the Brillouin-zone center, and to assign the eigenenergy accordingly. However, when k is far away from the zone center, all components of the eigenfunction are comparable, because there is strong valence-band mixing, so that we cannot assign the eigenenergies as light-hole-like or heavy-hole-like. We find that when the stress is applied parallel (perpendicular) to the quantum-well layers, valence-band mixing can (cannot) be induced by this external perturbation even if k is near the zone center. Finally, we report that the effective masses of certain subbands can be zero or ±∞ depending on the directions and the magnitudes of the uniaxial stress.