Screening phenomena in quantum wells
The electrical conductivity of the 2DHG formed at the interface has been measured on samples with composition 0.05<x<0.29 and carrier sheet densities between and in the temperature range 0.3 K to 1.6 K. It is found that the temperature (T) dependence is described by the superposition of a screening term linear in T and a logarithmic term associated with weak localization and carrier - carrier interactions. We find no evidence for a screening term with a dependence as has been predicted as a consequence of lifetime broadening. The results are in satisfactory quantitative agreement with Gold and Dolgopolov's theory of screening of short-range scattering centres.