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Pair-correlations and magnetic susceptibility of small Al-grains

N. K. Kuzmenko·V. M. Mikhajlov·S. Frauendorf
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Abstract

Paircorrelations and the magnetic susceptibility of electrons in a spherical cavity are studied both for grand canonical and the canonical ensemble. The coupling constant of the $BCS$ Hamiltonian is adjusted to experimental values of the gap parameter. The gap parameter is found to increase for small grains as a consequence of the pronounced shell structure in the spectrum of the spherical cavity. The sharp phase transition at $T_c$ is smeared out for the canonical ensemble. The strong paramagnetic susceptibility of the normal electrons in the cavity is reduced by the superconductivity, but it remains positive.

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N. K. Kuzmenko, V. M. Mikhajlov, S. Frauendorf. 1998-08-10. Pair-correlations and magnetic susceptibility of small Al-grains. https://arxiv.org/abs/cond-mat/9807011

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