Correlations among lattice parameter, external pressure, and critical temperature Tc has been surveyed on fullerene superconductors with a wide range of lattice parameters and various valence states. The observed value of dTc/dP for Na2Rb0.5Cs0.5C60 and Li3CsC60, having small interfullerene separations, is about a few times larger than that of K3C60. In contrast, small dTc/dP values are found in fullerides with expanded unit cells, such as (NH3)xNaAA†C60 (A, A† = K, Rb and Cs) and A3Ba3C60. Interestingly, the chemical and physical pressure effects on Tc are considerably different in these fullerides with large interfullerene spacings. Our results suggest that the pressure dependence is scaled by an interfullerene distance when the interfullerene distances is small, but that this scaling fails when the unit cell is expanded.
|ジャーナル||Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals|
|出版ステータス||Published - 2000|
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