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arXiv · 1402.0071

Local measurement of the Eliashberg function of Pb islands: enhancement of electron-phonon coupling by quantum well states

Michael Schackert·Tobias Märkl·Jasmin Jandke·Martin Hölzer·Sergey Ostanin·Eberhard K. U. Gross·Arthur Ernst·Wulf Wulfhekel
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Abstract

Inelastic tunneling spectroscopy of Pb islands on Cu(111) obtained by scanning tunneling microscopy below 1K provides a direct access to the local Eliashberg function of the islands with high energy resolution. The Eliashberg function describes the electron-phonon interaction causing conventional superconductivity. The measured Eliashberg function strongly depends on the local thickness of the Pb nanostructures and shows a sharp maximum when quantum well states of the Pb islands come close to the Fermi energy. Ab initio calculations reveal that this is related to enhanced electron-phonon coupling at these thicknesses.

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Michael Schackert, Tobias Märkl, Jasmin Jandke, Martin Hölzer, Sergey Ostanin, Eberhard K. U. Gross, Arthur Ernst, Wulf Wulfhekel. 2014-02-01. Local measurement of the Eliashberg function of Pb islands: enhancement of electron-phonon coupling by quantum well states. https://doi.org/10.1103/physrevlett.114.047002

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