Hole subband non-parabolicities in strained Si/Si1 − xGexquantum wells

We study the hole subband non-parabolicities in undoped pseudomorphic Si/Si_{1 − x}Ge_xquantum wells, strained in the growth direction 100. We solve exactly the multiband effective mass equation that describes the heavy, light and split-off hole valence bands. The symmetries of the Luttinger–Kohn Hamiltonian of the system are used to decouple the degenerate subbands. We calculate the in-plane dispersion relations, investigate the importance of the inclusion of the split-off hole valence band in the Hamiltonian and comment on the resulted non-parabolicities. Resonance states are also obtained.