Effects of interfacial atomic segregation on optical properties of InAs/GaSb superlattices - art. no. 081305

Largely because of the lack of detailed microscopic information on the inte rfacial morphology, most electronic structure calculations on superlattices and quantum wells assume abrupt interfaces. Cross-sectional scanning tunne ling microscopy (STM) measurements have now resolved atomic features of seg regated interfaces. We fit a layer-by-layer growth model to the observed ST M profiles, extracting surface-to-subsurface atomic exchange energies. Thes e are then used to obtain a detailed simulated model of segregated InAs/GaS b superlattices with atomic resolution. Applying pseudopotential calculatio ns to such structures reveals remarkable electronic consequences of segrega tion, including a blueshift of interband transitions, lowering of polarizat ion anisotropy, and reduction of the amplitude of heavy-hole wave functions at the inverted interface.