Electrical conductivity of a low-temperature two-dimensional medium

Vul B. M., Zavaritskaya E. I., Zavaritskii V. N.

The surface conductivity σ_{π} of the (111) face of a germanium crystal has been studied over the temperature *(T) *interval from 1.2 to 4.2 K. At *σ*_{α} S (e^{2}/h ) the surface conductivity *σ*_{π} varies in proportion to exp( — *e/kT), *where *e *is the electron charge, *h *is the Planck constant, and *e *is the activation energy. At σ_{α} £ *{e*^{2}/h) the behavior of the conductivity is described by *Ασ — σ*_{Ώ}(Τ_{χ}) *— **a*_{a}{T)~(e^{2}/4h )ln(7"j/r) as the temperature is lowered from 7\ = 4.2 К to 1.2 K. In the transition region the *σ*_{π}(Τ) dependence agrees quite well with both descriptions.