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TT: Fachverband Tiefe Temperaturen

TT 19: Poster Session: Correlated Electrons 1

TT 19.14: Poster

Montag, 20. März 2017, 15:00–19:00, P2-EG

Novel Quantum Criticality in the Au-Al-Yb Quasicrystal — •Andreas Wörl¹, Shuya Matsukawa², Akito Sakai³, Noriaki Sato², and Philipp Gegenwart¹ — ¹Experimentalphysics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, Germany — ²Department of Physics, Graduate School of Science, Nagoya University, Japan — ³Institute for Solid State Physics, The University of Tokyo, Japan

The emergence of non-Fermi liquid behavior without tuning an external control parameter has been reported for several heavy-fermion materials lately. One prime example is the icosahedral quasicrystal Au₅₁Al₃₆Yb₁₅, which exhibits divergent behavior of magnetic susceptibility, χ⁻¹∝ T^0.51, and specific heat, C/T ∝ −lnT, in zero magnetic field [1].
To further resolve the nature of the non-Fermi liquid state, we report thermal expansion and magnetostriction measurements at ultra-low temperatures. The Grüneisen ratio, which is the most suitable physical quantity for the characterization of pressure sensitive quantum crititcal phenomena, gives no evidence of an intrinsically generated pressure sensitive quantum critical point. We conclude the formation of a novel critical state with the peculiarity of low pressure but high magnetic field sensitivity.

[1] K. Deguchi, S. Matsukawa, N. K. Sato, T. Hattori, K. Ishida, H. Takakura and T. Ishimasa, Nat. Mater. 11, 1013−1016 (2012)