Stability and electronic properties of InAs/InP strained superlattices

Results of all-electron full-potential local-density electronic-structure calculations on strained 1×1 (001) superlattices are presented. The in-plane lattice parameter and the anion-cation equilibrium distances are determined with use of the total-energy for lattice parameters to simulate (i) the case in which the InAs/InP system is considered to be grown in the free-standing mode and (ii) the case in which InAs is considered to be grown on an InP substrate. In both cases, the instability of the two superlattices to disproportionation is found to be rather small and mainly due to the deformation energy. Only a small amount of charge is transferred at the interface and the energy term related to this charge transfer tends to stabilize the structure. Studies on the effects of strain on the electronic properties (band gap and effective valence-band masses) of the superlattices show that the uniaxial distortion affects the shape and the relative position of the valence bands so that the transport properties might be adjusted by properly varying the strain.