Systems of interacting particles occupying a lattice can often be described by the so-called Hubbard model. This model has been studied extensively with cold atoms in optical lattices, where its parameters can be easily tuned. In a complementary approach, Buzzi et al. investigated the organic molecular superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br, which can be described by the model, and used light to modulate the Hubbard parameters. The frequency of the light was tuned to a vibrational mode of the molecular building block of this material. The photoexcitation caused the sample to (briefly) become superconducting at temperatures much higher than the critical temperature. Calculations indicated that this was a consequence of an unusual long-range state of doubly occupied lattice sites.
Phys. Rev. Lett. X 10, 031028 (2020).