著者

Ihara Y. Noda K. Kawamoto A.

出版者

American Physical Society

雑誌

Physical Review B (ISSN:10980121)

巻号頁・発行日

vol.90, no.4, pp.41107, 2014-07-25

被引用文献数

6

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The local electronic state at every crystallographically independent molecular site was separately investigated in the organic superconductor alpha-(BEDT-TTF)(2)NH4Hg(SCN)(4) using site-selective C-13-NMR spectroscopy. The density of states (DOS) at three molecular sites shows independent temperature variation, which is caused by the long-range Coulomb interaction. Comparing the present results with those for a nonsuperconducting counterpart alpha-(BEDT-TTF)(2)RbHg(SCN)(4), we found that the uniform DOS at two of three independent molecular sites is crucial to induce superconductivity. Taking the site-dependent DOS as a parameter, we constructed a phase diagram for a superconductor with long-range Coulomb interaction, an alpha-type BEDT-TTF family, and summarized the competition between charge instability and superconductivity.