Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 65: Quantum-Critical Phenomena II
TT 65.10: Vortrag
Mittwoch, 14. März 2018, 17:30–17:45, HFT-FT 131
Highly anisotropic strain dependencies in PrIr2Zn20 — •Andreas Wörl1, Takahiro Onimaru2, Yoshifumi Tokiwa1, Keisuke Matsumoto2, Toshiro Takabatake2, and Philipp Gegenwart1 — 1Experimentalphysics VI, Center for Electronic Correlations and Magnetism, University of Augsburg, Germany — 2Graduate School of Advanced Sciences of Matter, Hiroshima University, Japan
Exotic Kondo physics, driven by the hybridization between electric quadrupole moments and conduction electrons, generates novel metallic phases. In PrIr2Zn20 the local Td symmetry of the Pr-ions forms the non-Kramers ground-state doublet which is a key prerequisite to explore quadrupole driven states of matter. The material displays antiferroquadrupolar order at TQ = 0.11 K, which is suppressed by magnetic fields B≤5 T applied along the [001] direction. Superconductivity sets in at Tc = 0.05 K. The significant enhancement of Seebeck coefficient as well as anomalies in specific heat and electrical resistivity at the critical magnetic field at B=5 T prompted speculations about a quadrupolar quantum critical point. To clarify potential quadrupolar quantum criticicality, we investigated thermal expansion and magnetostriction parallel and perpendicular to magnetic fields B ∥[001]. Linear thermal expansion and magnetostriction display huge uniaxial anisotropy, whereby volume changes are vanishingly small. We conclude that magnetic field is not an effective parameter to tune the hybridization of localized 4f2 and conduction electrons in PrIr2Zn20 and exclude the formation of a quadrupolar quantum critical point at B≈ 5 T.