These parameters are very closely related to the effective masses of the holes in various valence bands. γ γ 1 and γ γ 2 describe the coupling of the | X ⟩ ⟩ , | Y ⟩ ⟩ and | Z ⟩ ⟩ states to the other states. The third parameter γ γ 3 relates to the anisotropy of the energy band structure around the Γ Γ point when γ γ 2 ≠ ≠ γ γ 3 .