Correlation Enhanced Electron-Phonon Coupling in FeSe/SrTiO₃ at a Magic Angle

2025/06/27 by Zou, Qiang, Sihi, Antik, Oli, Basu Dev +5 · 2 citations
#FOS: Physical sciences #Strongly Correlated Electrons (cond-mat.str-el)

paper · doi:10.48550/arxiv.2506.22435

Abstract

While a predictive theory for unconventional superconductivity in Fe-based superconductors remains elusive, an extensively debated aspect is the interaction between phonons and strongly correlated electrons, and its potential role in the pairing mechanism. Here, through the combination of first principles dynamical mean field theory calculations and epitaxial growth of the single-layer FeX (X=Se, S, Te) on SrTiO₃ (STO)(001) substrate, which facilitates the controlled distortion of the FeX₄ tetrahedron, we demonstrate an unique superconducting dome where the superconducting gap peaks at a `magic' angle of the FeX₄ tetrahedron and the electron-phonon coupling (EPC) for the A_1g mode is maximized for the FeSe film. Our findings uncover a significant role of electronic correlations in strengthening Cooper pairing in unconventional superconductors by enhancing EPC.

Citations

• A Topological Superconductor Tuned by Electronic Correlations
• Effective enhancement of the electron-phonon coupling driven by nonperturbative electronic density fluctuations
• Unraveling Enhanced Superconductivity in Single-layer FeSe through Substrate Surface Terminations
• Deciphering alloy composition in superconducting single-layer FeSe1-xSx on SrTiO3(001) substrates by machine learning of STM/S data

Cited by

• Symmetry-required Orbital Selectivity in Monolayer FeSe
• Impact of electronic correlations on the superconductivity of high-pressure CeH₉

Related

• The interactions between antiferromagnetism, tetrahedral sites and electron-phonon coupling in FeSe1-xTex and FeSe/SrTiO3
• Unraveling Enhanced Superconductivity in Single-layer FeSe through Substrate Surface Terminations
• Direct evidence of interfacial coherent electron-phonon coupling in single-unit-cell FeSe film on Nb-doped SrTiO3
• Dual Enhancement of Superconductivity in FeSe/SrTiO3 via Orbital and Correlation Synergy
• Atomic-site dependent pairing gap in monolayer FeSe/SrTiO₃(001)- (√(13) × √(13))