Quantitative reliability study of the Migdal-Eliashberg theory for strong electron-phonon coupling in superconductors

Johannes Bauer, Jong E. Han, and Olle Gunnarsson
Phys. Rev. B 84, 184531 – Published 28 November 2011

Abstract

We reassess the validity of the Migdal-Eliashberg (ME) theory for coupled electron-phonon systems for large couplings λ. Although model calculations have found that the ME theory breaks down for λ0.5, it is routinely applied for λ>1 to strong-coupling superconductors. To resolve this discrepancy, it is important to distinguish between bare parameters, used as input in models, and effective parameters, derived from experiments. We show explicitly that ME gives accurate results for the critical temperature and the spectral gap for large effective λ. This provides quantitative theoretical support for the applicability of the ME theory to strong-coupling conventional superconductors.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 2 August 2011

DOI:https://doi.org/10.1103/PhysRevB.84.184531

©2011 American Physical Society

Authors & Affiliations

Johannes Bauer1, Jong E. Han1,2, and Olle Gunnarsson1

  • 1Max-Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany
  • 2Department of Physics, SUNY at Buffalo, Buffalo, New York 14260, USA

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 84, Iss. 18 — 1 November 2011

Reuse & Permissions
Access Options
CHORUS

Article Available via CHORUS

Download Accepted Manuscript
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review B

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×