MINIGAP AND TRANSPORT IN A TWO-DIMENSIONAL ELECTRON-SYSTEM

Conductivities are calculated in a two-dimensional inversion layer on a Si surface slightly tilted from the (001) both in the presence and in the absence of a magnetic field. Existence of a minigap caused by valley splitting is shown to strongly affect the two-dimensional conductivities. The calculation is performed in the Boltzmann transport theory and also in the self-consistent Born approximation in the presence of short-range scatterers. Characteristic behavior of the conductivities near the minigap is very sensitive to the existence of slight intervalley scattering matrix elements which have completely been ignored previously. Intervalley scatterings are crucial in explaining various experimental results. © 1979, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.