Effect of strain on the band structure ofInxGa1−xAs

Angle-resolved photoemission measurements from normal-emission spectra have been used to determine the strain-induced changes in shape of the valence bands of ${\mathrm{In}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As alloys with In concentrations of 10%, 20%, 27%, and 30%. The data have been analyzed using an iterative technique in which the experimentally determined bulk bands are fitted by polynomials. Differences between the strained and unstrained bands show k-dependent shifts that are similar in all alloys studied and whose sign and magnitude have been reproduced in the calculations. We observe an increasing strain-induced shift with concentration as reported but the shift is of the opposite sign to that previously reported by other investigators.