Hopping conduction in p-type MoS2 near the critical regime of the metal-insulator transition

Abstract

We report on temperature-dependent charge and magneto transport of chemically doped MoS2, p-type molybdenum disulfide degenerately doped with niobium (MoS2: Nb). The temperature dependence of the electrical resistivity is characterized by a power law, rho(T) similar to T-0.25, which indicates that the system resides within the critical regime of the metal-insulator (M-I) transition. By applying high magnetic field (similar to 7 T), we observed a 20% increase in the resistivity at 2K. The positive magnetoresistance shows that charge transport in this system is governed by the Mott-like three-dimensional variable range hopping (VRH) at low temperatures. According to relationship between magnetic-field and temperature dependencies of VRH resistivity, we extracted a characteristic localization length of 19.8 nm for MoS2: Nb on the insulating side of the M-I transition.