Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 110: Superconductivity: Fe-based Superconductors – Theory

TT 110.7: Vortrag

Freitag, 20. März 2015, 11:15–11:30, H 2053

Inelastic Scanning Tunneling Microscopy in conventional and unconventional superconductors — •Patrik Hlobil, Jörg Schmalian, Wulf Wulfhekel, and Jasmin Jandke — Karlsruhe Institute of Technologie, Germany

Electron tunneling spectroscopy has been used extremely successful in order to verify the microscopic phonon pairing mechanism in conventional BCS superconductors using the Eliashberg theory. Nevertheless, earlier theories and experiments focused mainly on elastic tunneling processes. We present, motivated by recent experiments, a theoretical description of inelastic tunneling in STM in which an electrons tunnels from the tip into a BCS superconductor and coherently excites a phonon during the tunneling process. This additional channel enhances the measured conductivity and we show that if the superconductor is in the normal state, within some limitations, the derivative dσ/dV will be proportional to the Eliashberg function α2F. Additionally, the influence of the inelastic contributions on the tunneling spectrum in the superconducting state will be discussed. Finally, we generalize the theory to other bosonic excitations and focus on the question if inelastic tunneling could be used to unveil the electronic pairing mechanism in the iron pnictides.