Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 9: Cooperative phenomena: Spin structures and magnetic phase transitions

MA 9.7: Vortrag

Montag, 1. April 2019, 16:30–16:45, H53

Competition between Kondo and Kitaev Physics in a frustrated impurity coupled to a fermionic bath — •Tathagata Chowdhury, Ralf Bulla, and Achim Rosch — University of Cologne, Germany

Geometrically frustrated quantum impurities coupled to metallic leads have been shown to exhibit rich behavior with a quantum phase transition separating Kondo screened and local moment phases. Frustration in the quantum impurity can alternatively be introduced via Kitaev-couplings between different spins of the impurity cluster. We use the Numerical Renormalization Group (NRG) to study a range of systems where the quantum impurity comprising of a Kitaev cluster is coupled to a bath of non-interacting fermions. We characterize the ground state and intermediate unstable fixed points of the system in terms of the plaquette fluxes and determine the temperature dependence of the various crossover scales of the model. We also show that the model can be mapped at low temperatures to an effective two-impurity Kondo model.