J. Phys. IV France
Volume 114, April 2004
Page(s) 399 - 340

J. Phys. IV France
114 (2004) 399
DOI: 10.1051/jp4:2004114096

Charge disproportionation in the metallic state of ${\alpha} $-(BEDT-TTF) 2I 3

S. Moroto1, 1, K.-I. Hiraki1, Y. Takano1, Y. Kubo1, T. Takahashi1, H.M. Yamamoto2 and T. Nakamura3

1  Department of Physics, Gakushuin University, Mejiro, Toshima-ku, Tokyo 171-8588, Japan
2  RIKEN (The Institute of Physical and Chemical Research), Wako, Saitama 351-0198, Japan
3  Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan

13C-NMR measurements have been carried out on the quasi two-dimensional organic conductor, ${\alpha} $-(BEDT-TTF) 2I 3. We measured the angular dependence of 13C-NMR spectrum at several temperatures above metal-insulator transition temperature, 135 K (= $T_{\rm MI,})$. We found that charge (spin) disproportionation already exists in the metallic state and gradually develops as temperature approaches to $T_{\rm MI}$. Key words. 13C-NMR, Charge disproportination.

© EDP Sciences 2004