Low Temperature Physics group (Prof. Kobayashi’s group) has succeeded in finding the modification of the organic Mott insulators to the electronic conductive metal by x-ray irradiation. X-ray irradiated organic Mott insulators show large enhancement of the far infrared optical reflectivity, which indicates that conductive carriers are induced. This finding contributes not only for progress of the basic research on the organic conductors but also for developing the organic electronic devices for applications in future. This result was published in Physical Review Letters (vol. 101, No. 20, Nov. 14, 2008), and was introduced also by such press sources as Nikkan Kogyo Shimbun (Nov. 25th, 2008), the Chemical Daily (Nov. 26th), Asahi Shimbun (Nov. 28th) and Kagaku Shimbun (Dec. 5th).
Figure: Crystal structure of an organic Mott insulator. (left) The resistivity decreases after x-ray irradiation. (upper right) The optical reflectivity in the far infrared region increases with increasing the x-ray irradiation dose. (lower right) These results indicate that conductive carriers are induced in the organic crystal by x-ray irradiation.
Prof. Kobayashi’s group（Low Temperature Physics）