Superconducting dome in a gate-tuned band insulator.

Ye, J T; Zhang, Y J; Akashi, R; Bahramy, M S; Arita, R; Iwasa, Y · Science · 2012

basic_science · Level V

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Abstract

A dome-shaped superconducting region appears in the phase diagrams of many unconventional superconductors. In doped band insulators, however, reaching optimal superconductivity by the fine-tuning of carriers has seldom been seen. We report the observation of a superconducting dome in the temperature-carrier density phase diagram of MoS(2), an archetypal band insulator. By quasi-continuous electrostatic carrier doping achieved through a combination of liquid and solid gating, we revealed a large enhancement in the transition temperature T(c) occurring at optimal doping in the chemically inaccessible low-carrier density regime. This observation indicates that the superconducting dome may arise even in doped band insulators.