SKM 2023 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 63: Superconductivity: Theory
TT 63.4: Vortrag
Freitag, 31. März 2023, 10:15–10:30, HSZ 103
Coherence and pairing fluctuations in strongly correlated superconductors — •Niklas Witt1,2, Sergey Brener1, Yusuke Nomura3, Ryotaro Arita4,5, Alexander Lichtenstein1,2, and Tim Wehling1,2 — 1University of Hamburg, Germany — 2The Hamburg Centre for Ultrafast Imaging, Germany — 3Keio University Japan — 4University of Tokyo, Japan — 5RIKEN CEMS, Japan
The fundamental properties of superfluids and superconductors are determined by the spatial coherence of the macroscopic condensate. Central to this characterization is the knowledge of the coherence length ξ, as it specifies the relevant length scales for fluctuations pertinent to, e.g., the formation of vortex latices or magneto-thermal transport. While the description of ξ is well established in weak-coupling BCS theory and Eliashberg-theory, it is a generally unknown quantity in strongly correlated superconductors, where spatiotemporal fluctuations influence the critical temperature [1] and might underlie light-induced enhancement of superconductivity [2].
In this work, we establish a link to directly calculate the coherence length for superconductors with strong electron correlations from microscopic theories and first principles. We illustrate with the example of Alkali-doped fullerides (A3C60) how proximity of superconducting and Mott-localized states impact superconducting coherence, pairing fluctuations, and critical temperature. Our analysis shows Eliashberg-type behavior of strongly correlated superconductors.
[1] Emery & Kivelson, Nature 374 (1995)
[2] Fausti et al., Science 331 (2011)
Mitrano et al., Nature 530 (2016)