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arXiv · 2310.05760

Strong terahertz third-harmonic generation by kinetic heavy quasiparticles in CaRuO$_3$

C. Reinhoffer·Sven Esser·Sebastian Esser·E. A. Mashkovich·S. Germanskiy·P. Gegenwart·F. Anders·P. H. M. van Loosdrecht·Zhe Wang
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Abstract

We report on time-resolved nonlinear terahertz spectroscopy of a strongly correlated ruthenate, CaRuO$_3$, as a function of temperature, frequency and terahertz field strength. Third-harmonic radiation for frequencies up to 2.1 THz is observed evidently at low temperatures below 80 K, where the low-frequency linear dynamical response deviates from the Drude model and a coherent heavy quasiparticle band emerges by strong correlations associated with the Hund's coupling.Phenomenologically, by taking an experimentally observed frequency-dependent scattering rate, the deviation of the field driven kinetics from the Drude behavior is reconciled in a time-dependent Boltzmann description, which allows an attribution of the observed third-harmonic generation to the terahertz field driven nonlinear kinetics of the heavy quasiparticles.

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C. Reinhoffer, Sven Esser, Sebastian Esser, E. A. Mashkovich, S. Germanskiy, P. Gegenwart, F. Anders, P. H. M. van Loosdrecht, Zhe Wang. 2023-10-09. Strong terahertz third-harmonic generation by kinetic heavy quasiparticles in CaRuO$_3$. https://doi.org/10.1103/physrevlett.132.196501

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