Intrinsic limit to low-temperature mobility in semiconductor structures with two-dimensional electrons

摘要

We consider theoretical aspects of the intrinsic limit to low-temperature mobility μ in semiconducting structures with single heterojunctions, taking into account the scattering of the two-dimensional (2D) carriers by piezoelectric acoustic phonons. We find that the reduction of the concentration of 2D carriers to n_s = 4.2 × 10~(11) cm~(-2) in the region of small-angle scattering will result in a mobility as high as 110 × 10~6 cm~2 (V s)~(-1) at T = 1.6 K. Since the maximum mobility depends on the concentration of carriers as n_s~(5/2) , it grows up to 320 × 10~6 cm~2 (V s)~(-1) at n_s = 8.2 × 10~(11) cm~(-2) and approximately the same temperature T=1.5K. Detailed numerical results are presented as a function of 2D carrier density and temperature and serve as a guide to experimentalists who wish to achieve peak carriers' mobility.