Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 69: Focus Session: Superconductivity in the Vicinity of a Quantum Critical Point
TT 69.6: Vortrag
Donnerstag, 23. März 2017, 17:45–18:00, HSZ 03
THz response of CeCoIn5 and evolution of effective mass in the non-Fermi liquid regime — Uwe S. Pracht1, Martin Dressel1, Jernej Mravlje2, Peter Wölfle3, Ryota Endo4, Tatsuya Watashige4, Yousuke Hanaoka4, Masaaki Shimozawa5, Takahito Terashima4, Takasada Shibauchi5, Yuji Matsuda4, and •Marc Scheffler1 — 11. Physikalisches Institut, Universität Stuttgart, Germany — 2Jozef Stefan Institute, Ljubljana, Slovenia — 3Karlsruhe Institute of Technology, Karlsruhe, Germany — 4Kyoto University, Kyoto, Japan — 5University of Tokyo, Chiba, Japan
CeCoIn5 is a heavy-fermion superconductor that exhibits non-Fermi-liquid properties in the metallic state below 30 K that are interpreted in terms of quantum criticality. The strong evolution of the quasiparticle effective mass with temperature or energy, which is characteristic for heavy fermions, takes place in this normal-state regime, but is typically difficult to access experimentally. Optical spectroscopy on metals can reveal the temperature- and frequency-dependent effective mass and transport scattering rate in and beyond the quantum-critical regime.
Here we perform THz spectroscopy on CeCoIn5 thin films in wide temperature (3 K to 150 K) and frequency (0.2 THz to 1.1 THz) regions that match in energy [1], and we employ an extended Drude analysis. We find strong frequency and temperature dependence of the scattering rate and the effective mass, and we discuss the implications for understanding the evolution of the heavy-fermion, non-Fermi-liquid state of CeCoIn5.
[1] U.S. Pracht et al., J. Magn. Magn. Mater. 400, 31 (2016).