Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 11: CE: Low-dimensional Systems - Materials 2
TT 11.2: Talk
Tuesday, March 23, 2010, 09:45–10:00, H18
Raman scattering evidence for a cascade-like evolution of the charge-density-wave collective amplitude mode — •Hans-Martin Eiter1, Michela Lavagnini2, Leonardo Tassini1, Bernhard Muschler1, Jiun-Haw Chu3, Nancy Ru3, Ian R. Fisher3, Leonardo Degiorgi2, and Rudi Hackl1 — 1Walther Meissner Institute, Bavarian Academy of Sciences and Humanities, 85748 Garching — 2Laboratorium für Festkörperphysik, ETH - Zürich, CH-8093 Zürich, Switzerland — 3GLAM, Stanford University, CA 94304, USA
We report results of Raman scattering experiments as a function of temperature on the charge-density-wave (CDW) systems DyTe3 and on LaTe3 at 6 GPa applied pressure. We clearly identify the unidirectional collective CDW amplitude excitation and follow their temperature dependence in the range from 6 K to 311 K. Surprisingly, we discover that the amplitude mode develops as a succession of two mean-field, BCS-like transitions at two different temperatures.
Tri-tellurides with heavier rare-earth atoms (i.e. Tm, Er, Ho, Dy) undergo another phase transition to a bidirectional CDW at low temperatures. In DyTe3 we find spectroscopic evidence for the amplitude mode excitation associated with the bidirectional CDW occuring below 50 K.
This work is supported by the DFG under Grant No. Ha2071/5-1.