A phase diagram for light-induced superconductivity in $\kappa$-(ET)${}_2$-X

Resonant optical excitation of certain molecular vibrations in $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Br has been shown to induce transient superconducting-like optical properties at temperatures far above equilibrium $T_c$. Here, we report experiments across the bandwidth-tuned phase diagram of this class of materials, and study the Mott insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl and the metallic compound $\kappa$-(BEDT-TTF)${}_2$Cu(NCS)${}_2$. We find non-equilibrium photoinduced superconductivity only in $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Br, indicating that the proximity to the Mott insulating phase and possibly the presence of preexisting superconducting fluctuations are pre-requisites for this effect.