The role of phonons in antiferromagnetic spin-fluctuation mediated superconductors within FLEX approximations.
ORAL
Abstract
The physics of phonon mediated conventional superconductors is well explained by the Bardeen-
Cooper-Schrieer (BCS) theory. However, the role of phonons in unconventional superconduc-
tors such as the cuprates is still not fully understood. It has been suggested that the electron-
phonon coupling due to forward-scattering or buckling mode generally helps cooper pairing,
and therefore enhances the transition temperature Tc. Here, we consider a tight-binding model typical for cuprates and treat the Coulomb interaction U within Fluctuation-Exchange (FLEX) approximations together with a momentum dependent electron-phonon coupling in a fully self-consistent Migdal-Eliashberg formalism. In the simulations, the Tc were estimated for various U and electron-phonon coupling constant λ for three types of phonon modes. The in-plane breathing mode mostly suppresses Tc while out-of-plane buckling mode and forward scattering phonons can enhance Tc; however, depending on the values of U and λ, the Tc is not always enhanced or suppressed in either case. Finally, the single-particle spectral function with/without phonons will also be shown.
Cooper-Schrieer (BCS) theory. However, the role of phonons in unconventional superconduc-
tors such as the cuprates is still not fully understood. It has been suggested that the electron-
phonon coupling due to forward-scattering or buckling mode generally helps cooper pairing,
and therefore enhances the transition temperature Tc. Here, we consider a tight-binding model typical for cuprates and treat the Coulomb interaction U within Fluctuation-Exchange (FLEX) approximations together with a momentum dependent electron-phonon coupling in a fully self-consistent Migdal-Eliashberg formalism. In the simulations, the Tc were estimated for various U and electron-phonon coupling constant λ for three types of phonon modes. The in-plane breathing mode mostly suppresses Tc while out-of-plane buckling mode and forward scattering phonons can enhance Tc; however, depending on the values of U and λ, the Tc is not always enhanced or suppressed in either case. Finally, the single-particle spectral function with/without phonons will also be shown.
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Presenters
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Ken Nakatsukasa
Physics, Univ of Tennessee, Knoxville
Authors
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Ken Nakatsukasa
Physics, Univ of Tennessee, Knoxville
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Yan Wang
Physics, University of Sherbrooke, Université de Sherbrooke, Physics, Université de Sherbrooke
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Steven Johnston
Univ. of Tennessee, Univ of Tennessee, Physics, Univ of Tennessee, Knoxville, Physics and Astronomy, University of Tennessee, Department of Physics and Astronomy, University of Tennessee, Physics, Univ. of Tennessee, physics and astronomy, University of Tennessee, Department of Physics and Astronomy, Univ of Tennessee, Knoxville