We report the X-ray irradiation effect on the superconductivity in the organic superconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br which is located nearby the Mott insulator-metal transition. The superconducting transition temperature Tc decreases almost linearly with increasing irradiation dose. The suppression rate of Tc for irradiation dose is larger than that reported so far in κ-(BEDT-TTF)2Cu(NCS) 2. The difference in the suppression of Tc between two organic superconductors might result from the different anion molecules, which may be altered by the X-ray irradiation, and the different strength of the electron correlation.
- Organic superconductor
- X-ray irradiation