Low-temperature conductivity of silicon doped with antimony

A detailed analysis of the experimental temperature dependences of the resistivity of silicon doped with arsenic with a concentration of 10$^{18}$ cm$^{-3}$ is performed for the region 1.8 K $< T <$ 25 K. It is shown that, as a result of cooling to a temperature lower than 4.5 K, a transition from the Mott mode with variable hopping length to the mode of hopping conduction via nearest neighbors is observed, while, at $T <$ 2.5 K, a transition to the Shklovskii–Efros mechanism is possible. A model for such a temperature crossover is suggested; the model is based on simplified solution of the percolation problem with the use of an interpolation expression for the density of states. Performed estimates show that the model is in satisfactory agreement with experimental data when the minimum number of adjustable parameters are used.