A 24-k • p model is used to compute the principal effective-mass parameters at , X and L valleys in a direct-band-gap semiconductor (GaAs) as well as an indirect-band-gap semiconductor (Si). The values of the effective masses for electrons, heavy holes and light holes in the , X and L valleys are in very good agreement with those reported in other publications. Satisfactory agreement with available experimental data is also obtained by this model. The Luttinger parameters and interband momentum matrix elements proposed in this work are consistent with the previous publications.

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We study the effects of the pc–pc coupling in intersubband hole optical transitions in SiGe/Si quantum wells for x and z polarizations. We have used a k⋅p model taking into account both the p-like first conduction band and the s-like second conduction band. First, we have found a unitary transformation that block diagonalizes the 14×14 Hamiltonian (or 12×12 Hamiltonian) into two 7×7 (or 6×6) blocks that are real symmetric in the finite difference formulation. We find that pc–pc interaction plays a minimal role in intersubband optical transition for x and z polarizations. Moreover, our calculations clearly confirm that the pc–pv coupling favors intersubband transitions for an optical polarization parallel to the layer plane (x polarization). In addition, for z polarization, both s–pv and pc–pv interactions play an equal footing role in intervalence band transitions.