Intrinsic limit to low-temperature mobility in semiconductor structures with two-dimensional electrons
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 ns = 4.2 × 1011 cm−2 in the region of small-angle scattering will result in a mobility as high as 110 × 106 cm2 (V s)−1 at T = 1.6 K. Since the maximum mobility depends on the concentration of carriers as n5/2s, it grows up to 320 × 106 cm2 (V s)−1 at ns = 8.2 × 1011 cm−2 and approximately the same temperature T = 1.5 K. 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.