AC magneto-conductance in n-InP in the hopping regime

AC conductance measurements of lightly doped n-InP were carried out as a fu nction of: (a) frequency (omega) in the range of 110 Hz to 50 kHz; (b) temp erature (T) down to 0.05 K and (c) magnetic field (H) up to 50 kG. At low t emperatures, the AC conductivity was found to follow the relation sigma(ome ga) = A omega (s) withs being both magnetic field and temperature dependent , increasing as H is increased or T is decreased. The Summerfield quasi-uni versal scaling formula was applied and the scaling parameter was found to b e logA = -3.1 +/-0.2 suggesting a constant density of states at the Fermi l evel. At relatively high temperatures, a(w) decreases as T is increased and this is attributed to a possible backward destructive interference. The te mperature, T-p(H), at which sigma(omega) becomes maximum, follows a relatio n of the form T-p(H) - T-p(0) proportional to H-gamma with gamma = 2.2 +/- 0.2.