Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 9: Supraleitung: Eigenschaften, elektronische Struktur, Ordnungsparameter

TT 9.10: Vortrag

Dienstag, 9. März 2004, 12:15–12:30, H20

Renormalization of the electron-phonon coupling in the one-band Hubbard model — •Roland Zeyher and Erik Koch — Max-Planck-Institut für Festkörperforschung, Stuttgart

We investigate the effect of electronic correlations on the coupling of electrons to Holstein phonons in the one-band Hubbard model. We calculate the static electron-phonon vertex within linear response of Kotliar-Ruckenstein slave-bosons in the paramagnetic saddle-point approximation. Within this approach the on-site Coulomb interaction U strongly suppresses the coupling to Holstein phonons at low temperatures. Moreover the vertex function does not show particularly strong forward scattering. Going to larger temperatures kT∼ t we find that after an initial decrease with U, the electron-phonon coupling starts to increase with U. We show that this behavior is related to an unusual reentrant behavior from a phase separated to a paramagnetic state upon decreasing the temperature.