"Low temperature energy relaxation in a two-dimensional carrier system"*

We discuss mechanisms and available predictions for carrier thermalization in a two-dimensional quantum well, with the eye towards understanding regimes in which carrier interactions are prominent. Of primary interest to us is the value of the exponent u that controls the thermal power flow P between the 2-dimensional charged layer at a temperature T_e  and the environment  at a temperature T according to the frequently used form P~ T_e^u - T^u. We will review theory for the P(T) functions in the cases of piezoelectric and deformation electron-photon coupling, the effects of disorder on the exponent and the predictions for the so-called hydrodynamic regime  and compare these to energy relaxation measurements obtained in studies of transport in GaAs/AlGaAs quantum wells with a high interaction parameter r_s>20.