The Valence Band Structure of Tellurium. I. The k·p Perturbation Method

The valance band structure of tellurium near the corner of the Brillouin zone is derived, with the use of the group theory and the k · p perturbation method. The main features of the obtained valence band are the existence of the k z -linear term and of the trigonal warping about the k z axis. Because of the k z -linear term S k z , the uppermost valence band has a double maximum or a single maximum, depending on the ratio of S 2 /4 B | Δ 1 | larger or smaller than one, where Δ 1 and B are the spin-orbit interaction and band parameters, respectively. The present theory is also applicable to selenium.