The observation of localisation and interaction effects in the two-dimensional electron gas of a GaAs-GaAlAs heterojunction at low temperatures

Abstract

The authors have investigated the logarithmic correction to the transport properties of the two-dimensional electron gas at the (modulation-doped) GaAs-GaAlAs interface in the temperature range 4.2-0.34K. GaAs is different to Si in that, due to the low density of states, the electron screening length is greater. This allows the existence of a significant logarithmic correction from the electron-electron interaction in the absence of a magnetic field. The experimental results are consistent with the co-existence of localisation and interaction effects although the analysis is complicated by the occupation of two sub-bands. They have investigated the electron-electron scattering rate and find that, as in the Si inversion layer, the temperature dependence is reduced by quantum corrections. Analysis of the rate of emission of phonons by hot electrons indicates that the phonons of importance are two-dimensional.