Local Spin Susceptibility Characteristic of Zero-Gap State of $\alpha$-(BEDT-TTF)2I3 under Pressure

We performed 13 C-NMR measurements in the metallic state of $\alpha$-(BEDT-TTF) 2 I 3 under pressure to determine the local spin susceptibility at each BEDT-TTF molecular site. We found that the local susceptibility becomes quite different from molecule to molecule in a unit cell with approach to th...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2010-10, Vol.79 (10), p.104704-104704-7
Main Authors: Takano, Yoshiki, Hiraki, Ko-ichi, Takada, Yusuke, Yamamoto, Hiroshi M, Takahashi, Toshihiro
Format: Article
Language:English
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Summary:We performed 13 C-NMR measurements in the metallic state of $\alpha$-(BEDT-TTF) 2 I 3 under pressure to determine the local spin susceptibility at each BEDT-TTF molecular site. We found that the local susceptibility becomes quite different from molecule to molecule in a unit cell with approach to the zero-gap state (ZGS) under pressure. This is related to the charge disproportionation among molecular sites [named A (A$'$), B, and C]. We confirmed that the most/least positively charged site, the B/C molecule, carries the smallest/largest local susceptibility. We also confirmed the linear temperature dependence of the local susceptibility at low temperatures. These results are consistent with the theoretical calculation [Eur. Phys. J. B 67 (2009) 139] and should be considered as the characteristics of the ZGS.
ISSN:0031-9015
1347-4073
DOI:10.1143/JPSJ.79.104704