Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 5: Postersession Superconductivity: Materials - Fabrication and Properties
TT 5.13: Poster
Montag, 23. März 2009, 13:00–16:45, P1A
Organic Superconductors Revisited: STM imaging and DFT calculations of the bc plane of κ-(BEDT-TTF)2Cu(NCS)2 — Johannes M. Büttner1, •Carsten L. Rohr1, Florian A. Palitschka1, Natascha D. Kushch2, Mark V. Kartsovnik3, Werner Biberacher3, and Bianca A. Hermann1 — 1Dept. of Physics / CeNS, LMU Munich and Walther-Meissner-Institute (WMI), Munich, Germany — 2Institute of Problems of Chemical Physics, Russian Academy of Science, Chemogolovka, Moscow-region, 142432 Russia — 3Walther-Meissner-Institute (WMI) and TU Munich, Munich, Germany
Organic superconductors of the BEDT-TTF family are of a layered nature and show a pseudogap. Because of that, these materials are of high interest for the understanding of the physics of high-temperature superconductors. Due to the fragility of organic superconductor crystals caused by the weak charge-transfer bonding, we conducted a study on single crystals of drastically different age[1]:The surfaces of a ten years aged crystal and a freshly prepared κ-(BEDT-TTF)2Cu(NCS)2 crystal were imaged by scanning tunneling microscopy. The molecularly-resolved STM images of the bc plane of the crystals agree well with each other. The variation in brightness at the various positions of the molecules matches a new Density-Functional-Theory (DFT) simulation (Perdew-Wang91 gradient-corrected exchange-correlation functional) of the cationic layer, based on a crystal structure of [2]. Hence, we attribute this symmetry breaking of the BEDT-TTF dimers to intrinsic surface electronic states.