NUMERICALLY STABLE SECULAR EQUATION FOR SUPERLATTICES VIA TRANSFER-MATRIX FORMALISM AND APPLICATION TO INAS IN0.23GA0.77SB AND INAS/IN0.3GA0.7SB/GASB SUPERLATTICES/

The numerically stable, Hermitian secular equation for superlattices w ithin the envelope-function approximation [F. Szmulowicz, Phys. Rev. B 54, 11 539 (1996)] is derived via the transfer-matrix approach using Burt's boundary conditions. In the process, the tangents-only form of the secular equation is related to an earlier transfer matrix approach [L. R. Ram-Mohan, K. H. Yoo, and R. L. Aggarwal, Phys. Rev. B 38, 615 1 (1988)] and extended to structures with an arbitrary number of layer s per superlattice period. The formalism is applied to superlattices w ith two (InAs/In0.23Ga0.77Sb) and three (InAs/In0.3Ga0.7Sb/GaSb) layer s per superlattice period, which are of interest for infrared detector and infrared cascade-laser applications, respectively. [S0163-1829(98 )03015-X].