Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

TT: Fachverband Tiefe Temperaturen

TT 34: Superconductivity: Theory

TT 34.2: Vortrag

Mittwoch, 19. März 2025, 15:15–15:30, H36

From charge fluctuations to pairing instabilities: Nonperturbative enhancement of the electron-phonon coupling driven by electronic correlations — •Emin Moghadas¹, Matthias Reitner¹, Alexander Kowalski², Giorgio Sangiovanni², Sergio Ciuchi^3,4, and Alessandro Toschi¹ — ¹Institute of Solid State Physics, TU Wien, Vienna, Austria — ²Institut für Theoretische Physik und Astrophysik and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, Würzburg, Germany — ³Dipartimento di Scienze Fisiche e Chimiche, Università dell'Aquila, Coppito-L'Aquila, Italy — ⁴Istituto dei Sistemi Complessi, CNR, Roma, Italy

We present a thorough investigation of the nonperturbative electronic mechanisms, which could lead to significant enhancements of the electron-phonon coupling in strongly correlated electron systems. Using dynamical mean-field theory (DMFT) for the single band Hubbard model on the square lattice, we analyze corrections to second-order electron-phonon processes arising from electronic fluctuations near the Mott metal-to-insulator transition (MIT). In this regime, the isothermal charge response becomes particularly large at small momenta, indicating tendencies towards phase-separation instabilities and enabling a substantial enhancement of the effective electron-phonon coupling. Eventually, we critically discuss the impact of our findings on observable spectral quantities as well as possible implications for the emergence of pairing instabilities.

Keywords: Strongly correlated electron systems; Unconventional superconductivity; Dynamical mean field theory; electron-phonon interactions; Hubbard model