Specific heat jump in BCS superconductors |
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Authors: | R Kishore S Lamba |
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Institution: | (1) Instituto Nacional de Pesquisas Espaciais, C.P. 515, S.J. Campos, S.P. 12201-970, Brazil, BR |
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Abstract: | An exact analytical expression for the specific heat jump at the critical temperature Tc has been obtained directly from the BCS gap equation for any shape of the energy dependent electronic density of states (DOS).
We consider a model which takes into consideration electron-electron repulsion, formulated in the Hubbard model along with
the electron-electron attraction due to electron-phonon interaction in the BCS formalism. We have analyzed this expression
for constant as well as for the Lorentzian forms of DOS. It is shown that the constant DOS in the simple BCS theory cannot
explain the large values of , found in some superconductors. The specific heat versus temperature curve has been found to have a peak, similar to that of Eliashberg theory of superconductivity. The influence
of repulsive interaction is very small and occurs mainly at higher temperatures.
Received: 26 January 1998 |
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Keywords: | PACS 74 20 Fg BCS theory and its development[:AND:] 74 20 -z Theories and models of superconducting state - 74 25 Bt Thermodynamic properties |
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