A study of the disordered alloy Ga1-xInxAs1-yPyby the variational multiple scattering method

Abstract

The authors apply, for the first time, the variational multiple scattering method (VMS) for the band calculation of a tridimensional disordered alloy. They calculated for the quaternary system Ga1-xInxAs1-yPy, with 0.605<or=x<or=0.917 and 0.094<or=y<or=0.845, lattice matched to InP. For all the alloy compositions, a unique potential for each element was used, chosen so that reasonable band structures for the pure semiconductors GaAs and InP result. No other adjustment was made. The energy density of states and the alloy bands were calculated for six compositions. The calculation is very fast when compared with similar calculations by the average t-matrix approximation method (ATA). The VMS method predicts, with the above potential choice, two separate inner peaks for the energy density of states, corresponding to the s As and s P bands, which is amenable to experimental verification. The importance of the self-consistent process in determining the degree of P and As p-band mixing is clearly shown.