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SYMB: Intersectional Symposium Many-Body Physics of Model Systems and Real Materials

SYMB 1: Many-Body Physics of Model Systems and Real Materials

SYMB 1.4: Hauptvortrag

Donnerstag, 17. März 2011, 16:00–16:30, HSZ 01

Influence of randomness on the Mott transition in the organic molecular conductors — •Takahiko Sasaki — Institute for Materials Research, Tohoku University, Sendai, Japan

Metal-insulator transitions are of considerable importance for strongly correlated electron systems. Among the various types of the transitions, the Mott transition due to electron-electron interactions is one of the most attractive phenomena. Another way of the electron localization originates from the interference of the electron wave functions due to randomness. This is the Anderson insulator derived by introducing disorder into the material. Since the randomness in the correlated electron system is essentially important in real materials, systematic studies of disorder effects are desired in systems nearby a Mott transition for understanding their physical properties. It has been known that x-ray irradiation for the organic materials causes molecular disorder softly and this remains permanently in organic material. Recently, it was found that the weak molecular disorder introduced by x-ray irradiation to the organic superconductor κ-(BEDT-TTF)₂Cu[N(CN)₂]Br induced the Anderson-type localization insulating state from the strongly correlated metallic/superconducting state [1]. In addition, the hydrostatic pressures to the localization insulator restore the metallic properties. These observations indicate that the stronger electron correlation upon approaching to the Mott transition enhances Anderson-type electron localization due to disorder introduced by x-ray irradiation.

[1] K. Sano, T. Sasaki et al., Phys. Rev. Lett. 101, 217003 (2010).