Efficient ab initio Migdal-Eliashberg calculation considering the retardation effect in phonon-mediated superconductors
Abstract
We formulate an efficient scheme to perform a Migdal-Eliashberg calculation considering the retardation effect from first principles. While the conventional approach requires a huge number of Matsubara frequencies, we show that the intermediate representation of the Green's function [H. Shinaoka et al., Phys. Rev. B 96, 035147 (2017), 10.1103/PhysRevB.96.035147] dramatically reduces the numerical cost to solve the linearized gap equation. Without introducing any empirical parameter, we obtain a superconducting transition temperature of elemental Nb (∼10 K), which is consistent with experiment. The present result indicates that our approach has a superior performance for many superconductors for which Tc is lower than O (10 ) K.
- Publication:
-
Physical Review B
- Pub Date:
- October 2020
- DOI:
- 10.1103/PhysRevB.102.134503
- arXiv:
- arXiv:2004.08591
- Bibcode:
- 2020PhRvB.102m4503W
- Keywords:
-
- Condensed Matter - Superconductivity
- E-Print:
- 8 pages, 4 figures