Onset of two-dimensional superconductivity in space charge doped few-layer molybdenum disulfide

Abstract Atomically thin films of layered materials such as molybdenum disulfide (MoS 2 ) are of growing interest for the study of phase transitions in two-dimensions through electrostatic doping. Electrostatic doping techniques giving access to high carrier densities are needed to achieve such phase transitions. Here we develop a method of electrostatic doping which allows us to reach a maximum n -doping density of 4 × 10 14 cm −2 in few-layer MoS 2 on glass substrates. With increasing carrier density we first induce an insulator to metal transition and subsequently an incomplete metal to superconductor transition in MoS 2 with critical temperature ≈10 K. Contrary to earlier reports, after the onset of superconductivity, the superconducting transition temperature does not depend on the carrier density. Our doping method and the results we obtain in MoS 2 for samples as thin as bilayers indicates the potential of this approach.