Partial-ordering effects inInxGa1−xP

We present a theoretical study for the band-gap energy and structural properties of partially ordered ${\mathrm{In}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$P alloys. Partially ordered alloys are modeled through a statistical ensemble of small crystal structures defined in a 64-site periodic cell. Configurations are generated according to the degree of ordering. The dependence of calculated properties on the long-range-order parameter is found to follow simple functional relationships. Structural anisotropies scale accurately with the square of the order parameter.