paper

Derivation of 12- and 14-band Hamiltonians for dilute bismide and bismide-nitride semiconductors

arXiv:1310.7969 · doi:10.1088/0268-1242/28/12/125025

Abstract

Using an tight-binding model we demonstrate how the observed strong bowing of the band gap and spin-orbit-splitting with increasing Bi composition in the dilute bismide alloy GaBiAs can be described in terms of a band-anticrossing interaction between the extended states of the GaAs valence band edge and highly localised Bi-related resonant states lying below the GaAs valence band edge. We derive a 12-band Hamiltonian to describe the band structure of GaBiAs and show that this model is in excellent agreement with full tight-binding calculations of the band structure in the vicinity of the band edges, as well as with experimental measurements of the band gap and spin-orbit-splitting across a large composition range. Based on a tight-binding model of GaBiNAs we show that to a good approximation N and Bi act independently of one another in disordered GaBiNAs alloys, indicating that a simple description of the band structure is possible. We present a 14-band Hamiltonian for ordered GaBiNAs crystals which reproduces accurately the essential features of full tight-binding calculations of the band structure in the vicinity of the band edges. The models we present here are therefore ideally suited to the simulation of the optoelectronic properties of these novel III-V semiconductor alloys.

Accepted for publication in Semiconductor Science and Technology

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