Deformation potential in a high-electron-mobility GaAs/Ga0.7Al0.3As heterostructure: Hydrostatic-pressure studies

We have studied scattering mechanisms and their pressure dependence in the high-electron-mobility heterostructure GaAs/${\mathrm{Ga}}_{0.7}$ ${\mathrm{Al}}_{0.3}$As. We concentrate on examination of two-dimensional–electron-gas scattering by acoustic phonons, which enables us to determine the magnitude of the deformation potential for GaAs in the considered heterostructure. The obtained value of ${\mathit{E}}_{\mathit{D}}$=-11.5±0.5 eV is in accordance with the most frequently reported data for GaAs/${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Al}}_{\mathit{x}}$As heterostructures. Contrary to the common assumptions about the pressure independence of ${\mathit{E}}_{\mathit{D}}$, we have found that its absolute value decreases with the applied hydrostatic pressure. A short discussion of this behavior is presented also.