Interface optical anisotropy in a heterostructure with different cations and anions

A theory of optical anisotropy and quantum-confined Pockels effect in CA/C'A'(001)quantum-well structures with different cations and anions, i.e. for C not equal C' and A not equal A', has been developed. The theory is based on a generalized effective-mass method, in which the boundary conditions for the envelope functions were constructed taking into account the mixing of heavy- and light-hole states under normal incidence of the hole on the interface. It is shown that an absorption anisotropy in interband transitions occurs for different mixing coefficients t(l-h) in the boundary conditions for the right- hand (A-C') and left-hand (A'-C) interfaces. An analysis is made of the interface contribution to the anisotropy induced by an external electric field for coinciding and different band offsets at the interfaces. The microscopic sp(3)s* tight-binding model is used to estimate the difference between the t(l-h) (A-C') and t(l-h) (A'-C) coefficients. (C) 1998 American Institute of Physics. [S1063-7834(98)03310-3].