HOLE REFRACTION FROM STRAINED SI1-XGEX/SI HETEROSTRUCTURES

The scattering problem of holes impinging towards Si1-xGex/Si heterointerfaces has been analyzed, within the envelope-function approach to the effective-mass approximation. A block-diagonalized 6×6 Luttinger-Kohn Hamiltonian is used to describe the dynamics of holes, which incorporates the mixing among the heavy-, light-, and spin-split-off hole bands, nonparabolicity, anisotropy, and built-in strain effects. Interesting anomalous reflectivities and transmissivities are found at certain threshold incident energies where any of the reflected or transmitted holes pass from evanescent to propagating. A generalization of the scattering-matrix formalism yields the symmetry relations among the reflection and transmission coefficients. © 1995 The American Physical Society.