Similarities and Differences in 2D `metallicity' induced by temperature   and parallel magnetic field: To screen or not to screen
  We compare the effects of temperature and parallel magnetic field on the two-dimensional metallic behavior within the unified model of temperature and field dependent effective disorder arising from the screened charged impurity scattering. We find, consistent with experimental observations, that the temperature and field dependence of resistivity should be qualitatively similar in n-Si MOSFET and very different in n-GaAs 2D metallic systems. 
S. Das Sarma and E. H. Hwang