Luttinger parameter

In semiconductors, valence bands are well characterized by 3 Luttinger parameters. At the Г-point in the band structure, ${\displaystyle p_{3/2}}$ and ${\displaystyle p_{1/2}}$ orbitals form valence bands. But spin–orbit coupling splits sixfold degeneracy into high energy 4-fold and lower energy 2-fold bands. Again 4-fold degeneracy is lifted into heavy- and light hole bands by phenomenological Hamiltonian by J. M. Luttinger.