Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Upper critical field in dirty two-band superconductors: Breakdown of the anisotropic Ginzburg-Landau theory
 

Summary: Upper critical field in dirty two-band superconductors:
Breakdown of the anisotropic Ginzburg-Landau theory
A. A. Golubov
Faculty of Science and Technology, University of Twente, 7500 AE Enschede, The Netherlands
A. E. Koshelev
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
Received 11 March 2003; published 4 September 2003
We investigate the upper critical field in a dirty two-band superconductor within quasiclassical Usadel
equations. The regime of very high anisotropy in the quasi-2D band, relevant for MgB2, is considered. We
show that strong disparities in pairing interactions and diffusion constant anisotropies for two bands influence
the in-plane Hc2 in a different way at high and low temperatures. This causes temperature-dependent Hc2
anisotropy, in accordance with recent experimental data in MgB2. The three-dimensional band most strongly
influences the in-plane Hc2 near Tc , in the Ginzburg-Landau GL region. However, due to a very large
difference between the c-axis coherence lengths in the two bands, the GL theory is applicable only in an
extremely narrow temperature range near Tc . The angular dependence of Hc2 deviates from a simple effective-
mass law even near Tc .
DOI: 10.1103/PhysRevB.68.104503 PACS number s : 74.20. z, 74.25.Op
I. INTRODUCTION
There is strong evidence of the multigap nature of super-
conducting state in the recently discovered1

  

Source: Alexei, Koshelev - Materials Science Division, Argonne National Laboratory

 

Collections: Materials Science; Physics