Optical modulation of effective on-site coulomb energy for the Mott transition in an organic dimer insulator

We report an optical modulation of the effective on-site Coulomb energy U on a dimer (U_{dimer}) for achieving the Mott insulator-to-metal transition in kappa-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Br, as investigated by pump-probe spectroscopy. A reduction of U_{dimer} is optically induced by molecule displace...

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Bibliographic Details
Published in:Physical review letters 2009-08, Vol.103 (6), p.066403-066403, Article 066403
Main Authors: Kawakami, Y, Iwai, S, Fukatsu, T, Miura, M, Yoneyama, N, Sasaki, T, Kobayashi, N
Format: Article
Language:English
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Summary:We report an optical modulation of the effective on-site Coulomb energy U on a dimer (U_{dimer}) for achieving the Mott insulator-to-metal transition in kappa-(BEDT-TTF)_{2}Cu[N(CN)_{2}]Br, as investigated by pump-probe spectroscopy. A reduction of U_{dimer} is optically induced by molecule displacement in the dimer under intradimer excitation. The mechanism of this metallization differs greatly from the photodoping-type mechanism reported previously. In contrast, a faster transition via the photodoping mechanism is detected for interdimer excitation. A metallic-domain-wall oscillation originating from the modulation of U_{dimer} was also observed near the critical end point of the Mott transition line.
ISSN:0031-9007
1079-7114
DOI:10.1103/physrevlett.103.066403