Energy relaxation of two-dimensional electrons and the deformation potential constant in selectively doped AlGaAs/GaAs heterojunctions

We investigate the electron heating process in selectively doped AlGaAs/GaAs heterojunctions from magnetotransport measurements at low temperatures. It is shown that the dominant energy-relaxation mechanism of the degenerate two-dimensional (2D) electrons for the electron temperature below 40 K is the emission of acoustic phonons via deformation potential coupling, and that the energy-loss rate is almost independent of 2D electron densities. From a detailed analysis it is derived that the deformation potential constant of the quantized 2D conduction band in GaAs is 11±1 eV.