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TT: Fachverband Tiefe Temperaturen
TT 87: Frustrated Magnets: Spin Liquids
TT 87.4: Talk
Friday, March 22, 2024, 10:15–10:30, H 3010
Kondo screening in Kitaev spin liquids with a Fermi surface — •Michel M. J. Miranda1,2 and Matthias Vojta1 — 1Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany — 2Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187 Dresden, Germany
Isolated magnetic impurities can be used to probe the low-energy properties of a host system, with the standard Kondo effect in metals being the paradigmatic example. Magnetic impurities have also been discussed as probes of quantum spin liquids and their excitations, and various approximate theoretical treatments have been put forward. In particular, it has been suggested that a spin liquid with a spinon Fermi surface would lead to Kondo screening akin to that in normal metals. Here we study this problem for a particular Kitaev model with a Majorana Fermi surface, realized on the square-octagon lattice. We present a numerically exact solution using Wilson's Numerical Renormalization Group (NRG) which generalizes previous work for the honeycomb-lattice Kitaev model. Our numerical data for the renormalization-group flow and for thermodynamic observables highlight important differences between the Kitaev system and a metal, related to the fractionalization scheme and the influence of the emergent gauge field.
Keywords: Frustrated magnetism; Spin liquids; Kitaev model; Fermi surface; Kondo impurity