A research group led by Professor Shinichiro Iwai at Graduate School of Science, Tohoku University has found a new mechanism that instantly turns organic dimer insulator into metal or superconductivity material by lights. The research has been conducted as an objective basic research supported by Japan Science and Technology Agency (JST.)

 

An injection method of conduction carriers by atomic substitution has been known as a method to turn insulators into metals. Insulators instantly turn into metals by replacing atomic substitution with light irradiation in the injection method. However, it needs high-intensity light irradiation that causes damages to materials by increasing the temperature of them.

 

The research group has succeeded in efficiently controlling insulator-metal transition without high-intensity light irradiation by the following; using organic materials that have two molecular pairs (dimer) as a structural unit, and light irradiation with a specific wavelength (near-infrared light.) The newly developed method changes molecular arrangements that make organic materials, and directly modulates effective on-site Coulomb energy between electrons that determines electron mobility by lights. This technology is different from the exiting injection method of light carriers, and expected to develop new physical phenomena including photoinduced superconductivity.

 

The research has been conducted in collaboration with Assistant Professor Takahiko Sasaki at Institute for Materials Research, Tohoku University.

 

The research results have been in “Physical Review Letters” (a scientific journal issued by American Physical Society) on August 7, 2009.   The paper’s title is _Optical modulation of effective on-site Coulomb energy for Mott transition in organic dimer insulator._

 

[Contact]

Professor Shinichiro Iwai

Department of Physics, Graduate School of Science, Tohoku University

Address: 6-3, Aoba, Aramaki, Aoba-ward, Sendai, Miyagi, 980-8578

Tel：+81-22-795-6423, Fax：+81-22-795-6362

E-mail：s-iwai@m.tains.tohoku.ac.jp

 

＜Abount JST Project＞

Mr. Masaya Kawamura

Department of Inclusive Research Administration, Innovation Headquarters, Japan Science and Technology Agency

Address: Kawaguchi Center Building 4-1-8, Honcho, Kawaguchi-shi, Saitama 332-0012 Japan

Tel: +81-48-226-5601 Fax: +81-48-226-5651

E-mail：crest@jst.go.jp