Scanning tunneling spectroscopy of proximity superconductivity in epitaxial multilayer graphene

Published

January 7, 2016

Author(s)

Donat F. Natterer, Jeonghoon Ha, Hongwoo H. Baek, Duming Zhang, William G. Cullen, Nikolai B. Zhitenev, Young Kuk, Joseph A. Stroscio

Abstract

Superconducting aluminum films were grown on multilayer graphene. The aluminum films were discontinuous with networks of trenches in the film morphology reaching down to the substrate to exposed graphene terraces. Superconductivity was induced in multilayer graphene by the proximity effect with the surrounding aluminum. Scanning tunneling spectra measured on the graphene terraces show a clear decay of the superconducting gap width with increasing distance from the graphene-aluminum edges. The spectra were well described by Bardeen-Cooper-Schrieffer (BCS) theory. The decay length for the superconducting order parameter in graphene was determined to be greater than 400 nm. Non-monotonous deviations in the exponentially decaying gap width appear to be correlated with subtle changes in graphene topography, possibly indicating graphene strain contributions to the superconducting order parameter.

Citation

Physical Review B

Volume

93

Issue

4

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevB.93.045406

Keywords

graphene, superconductivity, scanning tunneling microscopy

Citation

Natterer, D. , Ha, J. , Baek, H. , Zhang, D. , Cullen, W. , Zhitenev, N. , Kuk, Y. and Stroscio, J. (2016), Scanning tunneling spectroscopy of proximity superconductivity in epitaxial multilayer graphene, Physical Review B, [online], https://doi.org/10.1103/PhysRevB.93.045406 (Accessed April 18, 2024)