Electric break-throughs in vicinal planes of (001) Si inversion layers

Abstract

It is shown that intervalley couplings are closely related to the crystal potentials which open the band gaps at the center or the edge of the Brillouin zone. Tilted surfaces from (001) of Si n-channel inversion layers are investigated by using the extended zone effective mass theory developed by Ohkawa and Uemura. In the absence of a magnetic field, electric break-throughs and their interference effects cause various mini-gaps. They can explain a surface band structure proposed by Sham et al. Some mini-gaps have a large dependence on an azimuthal angle of tilting in the absence of shear strain. In the presence of a strong magnetic field, X break-through plays a major part in tilted surfaces, and Γ break-through in (001) surface. The valley splittings in Landau levels and their dependence on tilting angles are investigated. Finally, a brief remark is given to a long-standing controversy concerning the valley splittings in donor states and inversion layers.