Quantum critical transition from charge-ordered to superconducting state in the negative-U extended Hubbard model on a triangular lattice

We demonstrate a robust frustration-driven charge order to superconductivity transition in the half-filled negative-U extended Hubbard model. Superconductivity extends over a broad region of the parameter space. We argue that the model provides the correct insight to understanding unconventional superconductivity in the organic charge-transfer solids and other quarter-filled systems.