Disorder engineering and conductivity dome in ReS2 with electrolyte gating

TL;DR

This study investigates how electrolyte gating affects the electrical conductivity of ReS2, revealing a unique conductivity suppression in monolayers linked to disorder and localization, with implications for 2D material engineering.

Contribution

First demonstration of complete conductivity suppression in monolayer ReS2 due to electrolyte-induced disorder and localization effects.

Findings

Monolayer ReS2 exhibits complete conductivity suppression at high doping.

Thicker ReS2 layers show a conductivity dome but not full suppression.

Theoretical models attribute suppression to narrow conduction band and Anderson localization.

Abstract

Atomically thin rhenium disulphide (ReS2) is a member of the transition metal dichalcogenide (TMDC) family of materials characterized by weak interlayer coupling and a distorted 1T structure. Here, we report on the electrical transport study of mono- and multilayer ReS2 with polymer electrolyte gating. We find that the conductivity of monolayer ReS2 is completely suppressed at high carrier densities, an unusual feature unique to monolayers, making ReS2 the first example of such a material. While thicker flakes of ReS2 also exhibit a conductivity dome and an insulator-metal-insulator sequence, they do not show a complete conductivity suppression at high doping densities. Using dual-gated devices, we can distinguish the gate-induced doping from the electrostatic disorder induced by the polymer electrolyte itself. Theoretical calculations and a transport model indicate that the observed conductivity suppression can be explained by a combination of a narrow conduction band and Anderson localization due to electrolyte-induced disorder.