Simultaneous Control of Bandfilling and Bandwidth in Electric Double-Layer Transistor Based on Organic Mott Insulator κ-(BEDT-TTF)2Cu[N(CN)2]Cl

The physics of quantum many-body systems have been studied using bulk correlated materials, and recently, moire superlattices formed by atomic bilayers have appeared as a novel platform in which the carrier concentration and the band structures are highly tunable. In this brief review, we introduce an intermediate platform between those systems, namely, a band-filling- and bandwidth-tunable electric double-layer transistor based on a real organic Mott insulator kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl. In the proximity of the bandwidth-control Mott transition at half filling, both electron and hole doping induced superconductivity (with almost identical transition temperatures) in the same sample. The normal state under electric double-layer doping exhibited non-Fermi liquid behaviors as in many correlated materials. The doping levels for the superconductivity and the non-Fermi liquid behaviors were highly doping-asymmetric. Model calculations based on the anisotropic triangular lattice explained many phenomena and the doping asymmetry, implying the importance of the noninteracting band structure (particularly the flat part of the band).

Automated summary

The physics of quantum many-body systems have been explored using bulk correlated materials and moire superlattices. In this review, a band-filling- and bandwidth-tunable electric double-layer transistor is introduced as an intermediate platform for studying these systems. Experimental results on a real organic Mott insulator reveal both electron and hole doping induced superconductivity and non-Fermi liquid behaviors in the same sample. Model calculations based on an anisotropic triangular lattice explain many of these phenomena and the doping asymmetry, highlighting the importance of the noninteracting band structure.