Quantized Surface States of a Narrow-Gap Semiconductor

Quantized surface states in an inversion later of narrow-gap semiconductor with the zinc-blend structure are investigated theoretically by the effective mass approximation for nearly degenerate bands. When the band gap is small, and the spin-orbit interaction is large, the inversion asymmetry of surface potentioal causes large k -linear term in the two dimensional dispersion relation, which removes the spin degeneracy. Also, the g -factor becomes so large that the reversal of the ordering of the Landau levels is expected. The theory is applied to the analysis of the Schubnikov-de Haas measurements of Hg 0.79 Cd 0.21 ( ε G =68 meV, m 0 * =0.006 m). The inversion asymmetry splitting of the spin degeneracy is as large as several meV, and the inversion in the order of Landau levels is expected to be observed. The surface potentioal of the sample is expressed in the parametrized form, and values of the parameters are estimated by using the experimental data.