Regensburg 2013 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 59: Correlated Electrons: Quantum-Critical Phenomena - Experiments
TT 59.5: Talk
Thursday, March 14, 2013, 16:00–16:15, H6
Pressure- and Composition-Induced Structural Quantum Phase Transition in the Cubic Superconductor (Sr,Ca)3Ir4Sn13 — •Swee K. Goh1, Lina E. Klintberg1, Patricia L. Alireza1, Paul Saines2, David Tompsett1, Peter Logg1, Jinhu Yang3,4, Bin Chen3,4, Kazuyoshi Yoshimura4, and Malte Grosche1 — 1Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom — 2Department of Materials Science and Metallurgy, University of Cambridge, United Kingdom — 3Department of Physics, Hangzhou Normal University, China — 4Department of Chemistry, Kyoto University, Japan
The quasi-skutterudite superconductor Sr3Ir4Sn13 has been reexamined recently. In addition to a superconducting transition at Tc = 5 K, pronounced anomalies can be seen in magnetic susceptibility and resistivity at T* = 147 K. Using single crystal x-ray diffraction, we identify T* = 147 K as the temperature where the system undergoes a structural transition from a simple cubic parent structure (I-phase) to a superlattice variant (I’-phase) with a lattice parameter twice that of the I-phase. Applying physical pressure or chemical pressure (via the isoelectronic substitution of Ca for Sr) leads to a rapid suppression of T* = 147 K and an enhancement of Tc. Furthermore, a quasi-linear temperature dependence of resistivity is observed at the pressure where T* = 147 K extrapolates to 0 K, reminiscent of quantum critical phenomena on the border of magnetism. We argue that the pressure phase diagram of Sr3Ir4Sn13 features a superlattice quantum critical point.