Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 72: Poster Session: Correlated Electrons
TT 72.18: Poster
Mittwoch, 14. März 2018, 15:00–19:00, Poster B
Crystal growth and soft phonon mode of the quantum critical CDW system Lu(Pt1-xPdx)2In — •Thomas Gruner1, Stefan Lucas1, Satoshi Tsutsui2, Koji Kaneko3, Oliver Stockert1, and Christoph Geibel1 — 1MPI CPfS, Dresden, Germany — 2JASRI, SPring-8, Sayo, Hyogo, Japan — 3JAEA Quantum Beam Science Center, Tokai, Ibaraki, Japan
The connection between a charge density wave (CDW) quantum critical point (QCP) and superconductivity (SC) is presently a hot topic. We recently reported the discovery of a CDW in LuPt2In at TCDW=490 K, which can be continuously tuned to T=0 by partially substituting Pd for Pt [1]. Moreover, Lu(Pt1-xPdx)2In shows a sharp peak in the x dependence of the superconducting Tc just at the QCP, indicating a very unusual coupling between CDW and SC [1].
Here, we discuss the growth of large high-quality single crystals across the whole composition range. The challenge in growing them is the combination of high-melting elements with the low-melting In. We used these crystals for a series of momentum (Q) resolved inelastic x-ray scattering experiments. They provided a first insight into the Q, T and x dependence of the phonon softening connected with the CDW. In one phonon branch the phonon energy drops towards zero when T decreases towards TCDW(x) and Q approaches the CDW propagation vector. Our results provide an essential basis for analyzing the critical behaviour in this system. Furthermore, we present an improved structure model of the CDW state.
[1] T. Gruner et al., Nature Physics 13, 967-972 (2017)