https://doi.org/10.1140/epjb/e2009-00135-2
Organic superconductors revisited
STM imaging and DFT based simulations of the bc plane of κ-(BEDT-TTF)2Cu(NCS)2
1
Walther-Meissner-Institute (WMI) of Low Temperature Research of the Bavarian Academy of Science and Faculty of Physics/Center for Nano Science (CeNS), LMU Munich, Walther-Meissner-Strasse 8, 85748 Garching b. München, Germany
2
Institute of Problems of Chemical Physics, Russian Academy of Science, Chernogolovka, 142432 Moscow-region, Russia
3
Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany
4
Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching, Germany/Physik-Department, Technische Universität München, 85748 Garching, Germany
Corresponding author: a b.hermann@cens.de
Received:
5
August
2008
Revised:
4
March
2009
Published online:
15
April
2009
The surfaces of a ten years aged crystal and a freshly prepared κ-(BEDT-TTF)2Cu(NCS)2 crystal were compared by scanning tunneling microscopy (STM). The molecularly-resolved STM images of the bc plane of the crystals agree with each other and with the electronic contrast obtained by new density functional theory (DFT) based simulations. Even after ten years STM images of the molecular stacking of BEDT-TTF display a variation in brightness at the positions of different molecules. We attribute this symmetry breaking concerning the brightness in the STM images of the otherwise equivalent BEDT-TTF dimers to the electronic states of a relaxed surface.
PACS: 68.37.Ef – Scanning tunneling microscopy / 74.70.Kn – Organic superconductors / 71.15.Mb – Density functional theory, local density approximation, gradient and other corrections
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009
