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Substitution Effect by Deuterated Donors on Superconductivity in $κ$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Br

Naoki Yoneyama·Takahiko Sasaki·Norio Kobayashi
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Abstract

We investigate the superconductivity in the deuterated BEDT-TTF molecular substitution system $κ$-[(h8-BEDT-TTF)$_{1-x}$(d8-BEDT-TTF)$_x$]$_2$Cu[N(CN)$_2$]Br, where h8 and d8 denote fully hydrogenated and deuterated molecules, respectively. Systematic and wide range ($x$ = 0 -- 1) substitution can control chemical pressure finely near the Mott boundary, which results in the modification of the superconductivity. After cooling slowly, the increase of $T_{\textrm{c}}$ observed up to $x \sim$ 0.1 is evidently caused by the chemical pressure effect. Neither reduction of $T_{\textrm{c}}$ nor suppression of superconducting volume fraction is found below $x \sim$ 0.5. This demonstrates that the effect of disorder by substitution is negligible in the present system. With further increase of $x$, both $T_{\textrm{c}}$ and superconducting volume fraction start to decrease toward the values in $x$ = 1.

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Naoki Yoneyama, Takahiko Sasaki, Norio Kobayashi. 2004-02-04. Substitution Effect by Deuterated Donors on Superconductivity in $κ$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]Br. https://doi.org/10.1143/jpsj.73.1434

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