Mott variable-range hopping transport in a MoS2 nanoflake

Abstract

The transport characteristics of a disordered, multilayered MoS₂ nanoflake in the insulator regime are studied by electrical and magnetotransport measurements. The MoS₂ nanoflake is exfoliated from a bulk MoS₂ crystal and the conductance G and magnetoresistance are measured in a four-probe setup over a wide range of temperatures. At high temperatures, we observe that ln G exhibits a −T⁻¹ temperature dependence and the transport in the nanoflake dominantly arises from thermal activation. At low temperatures, where the transport in the nanoflake dominantly takes place via variable-range hopping (VRH) processes, we observe that ln G exhibits a −T^−1/3 temperature dependence, an evidence for the two-dimensional (2D) Mott VRH transport. Furthermore, we observe that the measured low-field magnetoresistance of the nanoflake in the insulator regime exhibits a quadratic magnetic field dependence ∼ αB² with α ∼ T⁻¹, fully consistent with the 2D Mott VRH transport in the nanoflake.