Regensburg 2016 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Correlated Electrons: Quantum-Critical Phenomena - Experiment
TT 28.10: Vortrag
Dienstag, 8. März 2016, 12:30–12:45, H21
CePdAl - a frustrated Kondo lattice at a quantum critical point — •Veronika Fritsch1,2, Akito Sakai1, Zita Hüsges3, Stefan Lucas3, Wolfram Kittler2, Christian Taubenheim2, Kai Grube2, Chien-Lung Huang2,3, Philipp Gegenwart1, Oliver Stockert3, and Hilbert v. Löhneysen2 — 1EP 6, Electronic Correlations and Magnetism, University of Augsburg, Germany — 2Karlsruhe Institute of Technology, Germany — 3Max Planck Institute for Chemical Physics of Solids, Dresden, Germany
CePdAl is one of the rare frustrated Kondo lattice systems that can be tuned across a quantum critical point (QCP) by means of chemical pressure, i. e., the substitution of Pd by Ni [1]. Magnetic frustration and Kondo effect are antithetic phenomena: The Kondo effect with the incipient delocalization of the magnetic moments, is not beneficial for the formation of a frustrated state. On the other hand, magnetic frustrated exchange interactions between the local moments can result in a breakdown of Kondo screening [2].
Furthermore, the fate of frustration is unclear when approaching the QCP, since there is no simple observable to quantify the degree of frustration. We present thermodynamic and neutron scattering experiments on CePd1−xNixAl close to the critical concentration x ≈ 0.14. Our experiments indicate that even at the QCP magnetic frustration is still present, opening the perspective to find new universality classes at such a quantum phase transition.
[1] V. Fritsch et al., PRB 89, 054416 (2014).
[2] T. Senthil et al. PRB 69, 035111 (2004).