We calculate the effect of local magnetic moments on the electron-phonon coupling in doped BaFe2 As2 using the density-functional perturbation theory. We show that the magnetism enhances the total electron-phonon coupling by ∼50%, up to λ≲0.35, still not enough to explain the high critical temperature, but strong enough to have a non-negligible effect on superconductivity, for instance, by frustrating the coupling with spin fluctuations and inducing order-parameter nodes. The enhancement comes not from the phonon softening but mostly from a renormalization of the electron-phonon matrix elements. We also investigate, in the rigid band approximation, the effect of doping, and find that λ versus doping does not mirror the behavior of the density of states; while the latter decreases upon electron doping, the former does not, and even increases slightly. © 2010 The American Physical Society.
Effects of magnetism and doping on the electron-phonon coupling in BaFe2As2 / Boeri, L.; Calandra, M.; Mazin, I. I.; Dolgov, O. V.; Mauri, F.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 82:2(2010). [10.1103/PhysRevB.82.020506]
Effects of magnetism and doping on the electron-phonon coupling in BaFe2As2
Calandra M.;
2010-01-01
Abstract
We calculate the effect of local magnetic moments on the electron-phonon coupling in doped BaFe2 As2 using the density-functional perturbation theory. We show that the magnetism enhances the total electron-phonon coupling by ∼50%, up to λ≲0.35, still not enough to explain the high critical temperature, but strong enough to have a non-negligible effect on superconductivity, for instance, by frustrating the coupling with spin fluctuations and inducing order-parameter nodes. The enhancement comes not from the phonon softening but mostly from a renormalization of the electron-phonon matrix elements. We also investigate, in the rigid band approximation, the effect of doping, and find that λ versus doping does not mirror the behavior of the density of states; while the latter decreases upon electron doping, the former does not, and even increases slightly. © 2010 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione