Fig. 2: Strain-tuning of κ-(BEDT-TTF)2Cu2(CN)3.
From: Chasing the spin gap through the phase diagram of a frustrated Mott insulator
a, b A 140 nm thin single-crystalline filament of κ-(BEDT-TTF)2Cu2(CN)3 was placed on a flexible PET substrate. Cooling from 300 K down to T → 0 imposes biaxial compression of order 1–2 kbar to the sample due to differential thermal contraction, yielding metallic and superconducting (SC) properties (red arrow in b). Uniaxial tensile strain εc along the c-axis is applied via bending of the substrate in order to tune from the Fermi liquid (FL) through the Mott MIT (blue arrow in b). b Crossover and transition temperatures from refs. 27,30,35, as indicated. c Resistance of the biaxially compressed crystal for different εc. Inset: SC below Tc ≈ 4 K for εc = 0 is evident in the log-log plot. Upon approaching the Mott state, SC is lost and the resistivity maxima at TBR shift to lower temperatures. In addition, our data reveal a reentrance of insulating behavior (magenta arrows) below T⋆ < TBR.
