Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 66: Superconductivity: Yu-Shiba-Rusinov and Andreev Physics
TT 66.12: Vortrag
Donnerstag, 21. März 2024, 12:30–12:45, H 3005
Kondo cloud of a partially screened impurity coupled to s-wave superconductor — •Anand Manaparambil1, Catalin Pascu Moca2,3, Gergely Zarand2, and Ireneusz Weymann1 — 1Adam Mickiewicz University, Poznan, Poland — 2Budapest University of Technology and Economics, Budapest, Hungary — 3University of Oradea, Oradea, Romania
Magnetic impurities coupled to a band of conduction electrons generate a many-body correlated state known as the Kondo state. The correlations in the Kondo state extend to large length scales compared to the size of the impurity. In general, the Kondo cloud has been predicted to extend up to micrometers in size and recent experiments have confirmed the presence of such large screening clouds. In the presence of superconducting correlations, such screening clouds have been shown to exist even outside the Kondo phase. In this work, we study a large spin Kondo model coupled to an s-wave superconductor. We show that there exists an underscreened Kondo doublet to an unscreened triplet phase transition according to the dominant energy scale. We observe different behaviors of the screening in both of the phases predicted analytically by the renormalized perturbation theory(RPT) and confirmed numerically using the Numerical Renormalization Group(NRG) methods. The spatial extension of the correlations estimated from the equal-time spin-spin correlation function calculated using the Density Matrix Renormalization Group (DMRG) corroborates the presence of screening clouds in both phases.
Keywords: Kondo cloud; Underscreened Kondo; superconductor; Yu-Shiba-Rusinov; Spatial correlations