Thermodynamics of Two-Band Superconductors: The Case of MgB2


Dolgov, Oleg V. and Kremer, Reinhard K. and Kortus, Jens and Golubov, Alexander A. and Shulga, Sergei V. (2005) Thermodynamics of Two-Band Superconductors: The Case of MgB2. Physical Review B: Condensed matter and materials physics, 72 (2). 024504. ISSN 1098-0121

open access
Abstract:Thermodynamic properties of the multiband superconductor MgB2 have often been described using a simple sum of the standard BCS expressions corresponding to sigma- and pi bands. However, it is a priori not clear if this approach is working always adequately, particularly in cases of strong interband scattering. Here we compare the often used approach of a sum of two independent bands using BCS-like alpha model expressions for the specific heat, entropy, and free energy to the solution of the full Eliashberg equations. The superconducting energy gaps, the free energy, the entropy, and the heat capacity for varying interband scattering rates are calculated within the framework of two-band Eliashberg theory. We obtain good agreement between the phenomenological two-band alpha model with the Eliashberg results, which delivers the theoretical verification to use the alpha model as a useful tool for a reliable analysis of heat capacity data. For the thermodynamic potential and the entropy we demonstrate that only the sum over the contributions of the two bands has physical meaning.
Item Type:Article
Copyright:© 2005 The American Physical Society
Science and Technology (TNW)
Research Group:
Link to this item:
Official URL:
Export this item as:BibTeX
HTML Citation
Reference Manager


Repository Staff Only: item control page

Metis ID: 225020