COUPLING BETWEEN TAU-TYPE AND X-TYPE ENVELOPE FUNCTIONS AT GAAS AL(GA)AS INTERFACES/

Connection rules for envelope functions related to the GAMMA- and X-po int conduction-band valleys in GaAs/Al(Ga)As systems are formulated in terms of a transfer matrix. The transfer-matrix elements are calculat ed using a method in which wave functions, which are obtained using em pirical pseudopotentials, are matched at the interface. The nonzero tr ansfer-matrix elements appear to depend weakly on energy which enables us to give a simple prescription for connection rules for envelope fu nctions in which r-x coupling is incorporated.