SINGLE-PARTICLE RELAXATION-TIMES AND SCATTERING TIMES IN A 2D ELECTRON-GAS

The authors examine the effect of the different spatial widths of successive subbands on the calculation of the single-particle relaxation and scattering times when up to two subbands are occupied. It is shown that, firstly, the single-particle relaxation time for the second subband is always larger (by a factor of two or more) than that for the ground subband and, secondly, the scattering time for the second subband is sometimes larger and sometimes smaller than that for the ground subband (depending on the electron concentration in the second subband) in qualitative agreement with recent experimental data.