Electron-phonon superconductivity mechanisms in the Hubbard model

Yuta Murakami, Philipp Werner, Naoto Tsuji +1 more

Marcin Mierzejewski, J. Zieliński, P. Entel

Marcin Mierzejewski, J. Zieliński

We discuss phonon-induced anisotropic superconductivity of strongly correlated quasiparticles within the two-dimensional Hubbard model. The generalized Fr\"olich-like canonical transformation leads to pairing interactions that become repulsive for vanishing concentration of holes but are attractive at low dopings. Our results indicate that the electron-phonon coupling in the presence of strong electron-electron correlations favors the formation of d-wave superconductivity.

Chan Minh Tien

Marcin Mierzejewski, J. Zieliński, P. Entel

We have addressed the problem of the influence of Coulomb correlations on the electron-phonon interaction in the two-dimensional Hubbard model. Both the energy and momentum dependence of the renormalization factor have been taken into account. We find that the superconducting properties of the system depend strongly on the phononic momentum and energy transfer values. This dependence is related to the symmetry of the superconducting order parameter. On one hand, the renormalization of the electron-phonon coupling function acts to the detriment of superconductivity in the s-wave channel. On the other hand, an enhancement of pairing correlations for anisotropic extended s-wave and d-wave superconductivity is observed.

Anh Tuan Hoang, Toan Thang Nguyen, Ngoc Thuan Nguyen