Magnetotransport properties of n-type GaAs in the hopping range

It appears that the predictions of percolation theory applied to the problem of impurity hopping in lightly doped semiconductors could be verified satisfactorily by measurements of the resistivity of n-type GaAs and its dependence on the magnetic field strength. Quantitative agreement was obtained for the dependence of the resistivity on the donor concentration and on a moderate magnetic field. For the case of strong magnetic fields a further refinement of the theory is required to establish an exact value for the numerical coefficient.