Anomalous Conductance near Percolative Metal-Insulator Transition in Monolayer MoS 2 at Low Voltage Regime.

Conductivity of the insulating phase increases generally at an elevated drain-source voltage due to the field-enhanced hopping or heating effect. Meanwhile, transport mechanism governed by percolation in low compensated semiconductor gives rise to the reduced conductivity at low field regime. Here, in addition to this behavior, we report the anomalous conductivity behavior to transform from percolative metallic to insulating phase at low voltage regime in monolayer molybdenum disulfide (MoS). Percolation transport at low source-drain voltage is governed by inhomogeneously distributed potential in strongly interacting monolayer MoS with substrate, distinct from quantum phase transition in multilayer MoS. At high source-drain voltage regime, the insulating phase is transformed further to metallic phase, exhibiting multi-phases of metallic-insulating-metallic transitions in monolayer MoS. These behaviors highlight MoS as a model system to study various classical and quantum transports as well as metal-insulator transition in two dimensional systems.