SCREENING PHENOMENA IN SI SI1-XGEX QUANTUM-WELLS/

The electrical conductivity of the 2DHG formed at the Si/Si1-xGex inte rface has been measured on samples with composition 0.05 < x < 0.29 an d carrier sheet densities between 1 x 10(11) cm(-2) and 1.1 x 10(12) c m(-2) in the temperature range 0.3 K to 1.6 K. It is found that the te mperature (T) dependence is described by the superposition of a screen ing term linear in T and a logarithmic term associated with weak local ization and carrier-carrier interactions. We find no evidence for a sc reening term with a T-2 dependence as has been predicted as a conseque nce of lifetime broadening. The results are in satisfactory quantitati ve agreement with Gold and Dolgopolov's theory of screening of short-r ange scattering centres.