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TT: Tiefe Temperaturen

TT 7: Superconductivity & Solids At Low Temperature - Poster Session

TT 7.35: Poster

Montag, 27. März 2006, 14:00–17:45, P1

Pressure-induced changes in the quasi-one-dimensional superconductor β-Na_0.33V₂O₅ studied by Raman spectroscopy — •S. Frank¹, C. A. Kuntscher¹, I. Gregora², T. Yamauchi³, and Y. Ueda³ — ¹1.Physikalisches Institut, Universität Stuttgart, D-70550 Stuttgart, Germany — ²Institute of Physics ASCR, Praha, Czech Republic — ³Institute for Solid State Physics, University of Tokyo, Tokyo

β-Na_0.33V₂O₅ is one of the first known inorganic quasi-one-dimensional superconductors. The pressure - temperature phase diagram is remarkable, showing a superconducting phase for pressures higher than 7 GPa in direct vicinity to a charge-ordered phase. The mechanism of the superconductivity and its relation to the charge ordering is not clear.

In a recent infrared study under pressure major changes in the reflectivity spectra were observed above 12 GPa, in particular the appearance of additional, relatively broad excitations [1]. A redistribution of charge with a possible relation to structural changes was suggested as a possible explanation. To obtain a deeper understanding of the changes occurring at 12 GPa we carried out polarization-dependent Raman spectroscopy under pressure at room temperature. The results are discussed in terms of a possible structural phase transition at 12 GPa.

Supported by the DFG, Emmy Noether-program.

[1] C.A. Kuntscher et al., Phys. Rev. B 71, 220502(R) (2005)