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DY: Fachverband Dynamik und Statistische Physik
DY 16: Nonequilibrium Quantum Systems 1 (joint session TT/DY)
DY 16.1: Talk
Tuesday, March 19, 2024, 09:30–09:45, H 3005
Periodically Driven Heavy-Fermion Systems — •Michael Turaev1 and Johann Kroha1,2 — 1Physikalisches Institut, Universität Bonn, Germany — 2School of Physics & Astronomy, University of St. Andrews, UK
In this work we study the effects of terahertz (THz) light irradiation on heavy-fermion systems. A typical model for such systems is the periodic Anderson model where strongly repulsive, localized electrons in the 4f shell of rare-earth ions hybridize with a sea of conduction electrons. The Kondo effect induces a new flat band of heavy-fermions, near the Fermi energy. Applying a stationary THz light field induces a time-periodic hybridization between the conduction and the 4f electrons, rather than a modulation of the on-site 4f energy, due to the dipole selection rules. On one hand, the Floquet theorem predicts that the periodic driving produces replicas of the Kondo resonance, centered around multiples of the driving frequency. However, the THz light field could also break up the Kondo singlets, thereby destroying the heavy-fermion state altogether.
To analyze such a scenario we use the non-equilibrium dynamical mean field theory (DMFT), combined with the Floquet-Keldysh Green function method. We obtain that for weak driving compared to the bare hybridization, the Kondo effect is preserved and Floquet replicas of the heavy-fermion bands are observed. However, a strong driving can lead to an efficient suppression of the Kondo effect where the spectral weight of the flat band is reduced.
Keywords: Kondo system; Periodic driving; Heavy Fermions; Dynamical mean field theory