Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 6: Scanning probe methods I
O 6.6: Vortrag
Montag, 26. März 2012, 11:45–12:00, MA 043
Determination of the electron-phonon coupling in ultra-thin Pb films with STM — •Tobias Märkl1, Michael Schackert1, Martin Hölzer2, Sergey Ostanin2, Arthur Ernst2, and Wulf Wulfhekel1 — 1KIT, Karlsruhe — 2MPI, Halle
The typical quantity to characterize the electron-phonon coupling of a material is the energy-dependent Éliashberg function α2F(ω) determining the superconducting properties of the material. It can be determined with tunneling spectroscopy in the superconducting state and inversion of the Éliashberg equations or directly using inelastic tunneling spectroscopy (ITS) in the normal state.
We used scanning tunneling microscopy (STM) at 1K in UHV to locally measure inelastic tunneling spectra of thin Pb films on Cu(100) and CuN/Cu(100) to determine α2F(ω) as function of the local Pb thickness. The films were prepared in situ with varying thickness up to 25 atomic layers and were in the normal state due to the proximity effect. We find a good agreement of the obtained Éliashberg function with ab initio calculations for bulk lead.