SKM 2021 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 1: Focus Session: Disordered and Granular Superconductors: Fundamentals and Applications in Quantum Technology I
TT 1.6: Vortrag
Montag, 27. September 2021, 12:00–12:15, H6
Low energy electrodynamics of strongly disordered superconductors — •Götz Seibold1, Lara Benfatto2, and Claudio Castellani2 — 1BTU Cottbus-Senftenberg, Cottbus, Germany — 2University of Rome ’La Sapienza’, Rome, Italy
In this contribution we will discuss the static and dynamical response of strongly disordered superconductors based on investigations of the attractive Hubbard model with strong on-site disorder and by including fluctuations beyond the Bogoljubov-de Gennes approach. It turns out that paramagnetic processes mediate the response of all collective modes, with a substantial contribution of charge/phase fluctuations [1,2,3]. In particular, we show that for strongly disordered superconductors phase modes acquire a dipole moment and appear as a subgap spectral feature in the optical conductivity which even survives long-range Coulomb interactions. The same processes turn out to dominate also the third-order current at strong disorder [5]. In this regard we show that disorder strongly influences the polarization dependence of the non-linear response, with a marked difference between the homogenous and the disordered case. Our results are particularly relevant for recent experiments in cuprates, whose band structure is in a first approximation reproduced by our lattice model.
[1] G. Seibold et al., Phys. Rev. B 92, 064512 (2015)
[2] T. Cea et al., Phys. Rev. B 89, 174506 (2014)
[3] G. Seibold et al., Phys. Rev. Lett. 108, 207004 (2012)
[4] G. Seibold et al., Phys. Rev. B 103, 014512 (2021)