EFFECTS OF ORDERING ON THE ELECTRON EFFECTIVE-MASS AND STRAIN DEFORMATION POTENTIAL IN GAINP2 - DEFICIENCIES OF THE K-CENTER-DOT-P MODEL

The conventional eight-band k . p model predicts a decrease of the electron effective mass and no dependence of the (001) strain band-gap deformation potential with the degree eta of long-range order in Ga0.5In0.5P alloys. We show that a complete band-structure approach predicts instead that (i) the electron effective mass in the ordering direction increases from 0.092m(0) for eta = 0 (random alloy) to 0.133m(0) for eta = 1 (ordered alloy), and (ii) the strain deformation potential decreases in magnitude from 8.26 eV for eta = 0 to 6.34 eV for eta = 1. These two effects are caused by the mixing of the conduction-band minimum with the L-derived conduction band, neglected in the standard eight-band model.