https://doi.org/10.1007/s100510050678
Specific heat jump in BCS superconductors
Instituto Nacional de Pesquisas Espaciais, C.P. 515,
S.J. Campos, S.P. 12201-970, Brazil
Received:
26
January
1998
Published online: 15 March 1999
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.
PACS: 74.20.Fg – BCS theory and its development / 74.20.-z – Theories and models of superconducting state / 74.25.Bt – Thermodynamic properties
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
