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DY: Fachverband Dynamik und Statistische Physik
DY 30: Quantum-Critical Phenomena (joint session TT/DY)
DY 30.1: Talk
Thursday, March 20, 2025, 09:30–09:45, H31
Missing Spectral Weight in a Paramagnetic Heavy-Fermion System — •Debankit Priyadarshi1, Jingwen Li1, Chia-Jung Yang1, Ulli Pohl2, Oliver Stockert3, Hilbert von Löhneyesen4, Shovon Pal5, Manfred Fiebig1, and Johann Kroha2,6 — 1ETH Zurich, Switzerland. — 2University of Bonn, Germany — 3Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 4Karlsruhe Institute of Technology, Germany — 5NISER, HBNI, Jatni, India. — 6University of St. Andrews, UK
Time-resolved terahertz spectroscopy (THz-TDS) has proven to be a powerful method to study the correlation dynamics in many-body systems, particularly heavy-fermions [1]. The competition between the Kondo screening effect and the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in these materials drives a quantum phase transition (QPT) between a magnetically ordered and a liquid-like ground state of heavy Kondo quasiparticles. These quasiparticles disintegrate near a quantum critical point (QCP). Using THz-TDS, we report a suppression in the quasiparticle spectral weight in CeCu6−xAux on the antiferromagnetic side of the QPT at temperatures much higher than the Neel temperature, which has a different origin from the suppression at QCP [2]. We study the paramagnetic phase of CeCu6−xAux with x = 0.2, 0.3, and 0.5 samples, and show that the suppression results from a quantum frustration effect induced by the temperature-independent RKKY interaction, which may influence material properties at QCP. [1] C. Wetli et al., Nat. Phys. 14, 1103 (2018);
[2] J.Li et al., arXiv:2408.07345 (2024).
Keywords: Strongly-correlated materials; heavy-fermions; Terahertz (THz) spectroscopy; quantum phase transition