Dependence of the band structure on the order parameter for partially ordered Ga{sub x}In{sub 1-x}P alloys

Description/Abstract

An empirical pseudopotential method is demonstrated for realistically and accurately calculating the band structure of partially CuPt ordered Ga{sub x}In{sub 1-x}P alloys. A sufficiently large supercell of {approx}3500 atoms, with all atomic positions relaxed by applying a valence force field method, is used to simulate the (Ga,In) distribution in the partially ordered alloy with the order parameter {eta} varying from 0 to 1. While agreeing very well with experimental data in the experimentally verifiable region {eta}<0.5, our results illustrate that a commonly accepted interpolation scheme (i.e., the {eta}{sup 2} rule) is grossly inaccurate for determining certain primary band structure parameters (e.g., the band gap) between {eta}=0 and {eta}=1.