Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 41: Correlated Electrons: Quantum-Critical Phenomena
TT 41.5: Talk
Wednesday, March 22, 2017, 10:30–10:45, HSZ 204
Grüneisen ratio divergence at the structural quantum critical point in (Ca0.9Sr0.1)3Rh4Sn13 — •Rudra Sekhar Manna1, Andreas Wörl1, Swee K. Goh2, Kazuyoshi Yoshimura3, and Philipp Gegenwart1 — 1EP VI, EKM, Augsburg University, 86159 Augsburg, Germany — 2Dept. of Physics, The Chinese University of Hong Kong, Hong Kong, China — 3Dept. of Chemistry, Kyoto University, Kyoto 606-8502, Japan
Quasi-skutterudite compound Sr3Rh4Sn13 shows a second-order structural phase transition at 138 K which can be tuned to 0 K either by applying hydrostatic pressure or by chemical pressure in (CaxSr1−x)3Rh4Sn13. At the critical concentration, xc = 0.9, specific heat shows a pronounced enhancement (compared to the x = 0) of the low-temperature phonon (T3) contribution, possibly related to the softening of an optical mode [1]. We have performed high-resolution thermal expansion and specific heat measurements on single crystal of x = 0 and a lump of small (Ca0.9Sr0.1)3Rh4Sn13 crystals. Thermal expansion also detects a strongly enhanced phonon contribution at the critical concentration. Importantly, the effective Grüneisen parameter Γeff = β·Vmol/κT·C diverges from 20 K down to below 1 K, providing evidence for quantum criticality.
[1] S. K. Goh, D. A. Tompsett, P. J. Saines, H. C. Chang, T. Matsumoto, M. Imai, K. Yoshimura, and F. M. Grosche, PRL 114, 097002 (2015).