Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 33: Postersession Correlated Electrons: Metal Insulator Transition, Spin Systems and Itinerant Magnets
TT 33.12: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Interplay between superconductivity and charge order in 2D organic superconductors — •Stefan Kaiser1, Natalia Drichko1, Yaxiu Sun1, Martin Dressel1, Toomas Room2, Dan Hüvonen2, Urmas Nagel2, Matteo Masino3, Alberto Girlando3, and John Schlueter4 — 11. Physikalisches Institut, Universität Stuttgart, Germany — 2KBFI, Tallinn, Estonia — 3Dip. Chimica G.I.F. and INSTM-UdR Parma, Italy — 4Material Science Division, Argonne National Laboratory, U.S.A.
Theoretical study of systems with quarter-filled conductance band and strong electron-electron correlations propose superconductivity mediated by charge order fluctuations [1]. We present IR reflectivity of a 1/4-filled organic superconductor β"-(BEDT-TTF)2SF5CH2CF2SO3 (Tc=5 K) in the frequency range between 8 and 10000 cm-1 at temperatures down to 1.8 K. Our spectroscopic study reveals a splitting of the charge-sensitive phonons showing charge order while transport properties show metallic behavior. The narrow Drude response and its interplay with charge fluctuations, evident in an electronic band, is responsible for superconductivity, with a superconducting gap of 12 cm-1 at 1.8 K. A comparison with the isostructural metal β"-(BEDT-TTF)2SF5CHFSO3 reflects the close relation between superconductivity and charge order.
[1]. J. Merino et al. Phys. Rev. Lett 87, 237002 (2001)