Intervalley conversion at a boundary. Microscopic model

A simple model is proposed which makes it possible to obtain correctly the boundary conditions on the envelope wave functions in the case of contact of materials with substantially different electron spectra (presence or absence of a side valley or substantial difference in its position). The passage of an electron through such a boundary is considered, and analytical expressions for the transmission coefficient and intervalley transition coefficient are found. The dependence of these coefficients on the parameters of the bounding materials and on the nature of the boundary turn out to be decisive for vertical transport phenomena. Possible consequences of efficient conversion at the boundaries in multilayer structures are discussed. Fiz. Tverd. Tela (St. Petersburg) 39, 839–843 (May 1997)