Two-dimensional ground-state mapping of a Mott-Hubbard system in a flexible field-effect device

Abstract

A Mott insulator sometimes induces unconventional superconductivity in its neighbors when doped and/or pressurized. Because the phase diagram should be strongly related to the microscopic mechanism of the superconductivity, it is important to obtain the global phase diagram surrounding the Mott insulating state. However, the parameter available for controlling the ground state of most Mott insulating materials is one-dimensional owing to technical limitations. Here we present a two-dimensional ground-state mapping for a Mott insulator using an organic field-effect device by simultaneously tuning the bandwidth and bandfilling. The observed phase diagram showed many unexpected features such as an abrupt first-order superconducting transition under electron doping, a recurrent insulating phase in the heavily electron-doped region, and a nearly constant superconducting transition temperature in a wide parameter range. These results are expected to contribute toward elucidating one of the standard solutions for the Mott-Hubbard model. Theoretical calculations reproducing the main features of our experimental results have also been conducted.

34 pages, 11 figures

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Cited by in corpus (4)

• Anomalous Hall effect in $\kappa$-type organic antiferromagnets
• Topological Doping and Superconductivity in Cuprates: An Experimental Perspective
• Simultaneous Control of Bandfilling and Bandwidth in Electric Double-Layer Transistor Based on Organic Mott Insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl
• Universal limiting transition temperature for the high $T_{\mathrm{c}}$ superconductors