Observation of Yu–Shiba–Rusinov States in Superconducting Graphene

Eva Cortés-del Río, Jose Luis Lado, Vladimir Cherkez, Pierre Mallet, Jean Yves Veuillen, Juan Carlos Cuevas, José María Gómez-Rodríguez, Joaquín Fernández-Rossier, Iván Brihuega*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

When magnetic atoms are inserted inside a superconductor, the superconducting order is locally depleted as a result of the antagonistic nature of magnetism and superconductivity. Thereby, distinctive spectral features, known as Yu–Shiba–Rusinov states, appear inside the superconducting gap. The search for Yu–Shiba–Rusinov states in different materials is intense, as they can be used as building blocks to promote Majorana modes suitable for topological quantum computing. Here, the first observation of Yu–Shiba–Rusinov states in graphene, a non-superconducting 2D material, and without the participation of magnetic atoms, is reported. Superconductivity in graphene is induced by proximity effect brought by adsorbing nanometer-scale superconducting Pb islands. Using scanning tunneling microscopy and spectroscopy the superconducting proximity gap is measured in graphene, and Yu–Shiba–Rusinov states are visualized in graphene grain boundaries. The results reveal the very special nature of those Yu–Shiba–Rusinov states, which extends more than 20 nm away from the grain boundaries. These observations provide the long-sought experimental confirmation that graphene grain boundaries host local magnetic moments and constitute the first observation of Yu–Shiba–Rusinov states in a chemically pure system.

Original languageEnglish
JournalAdvanced Materials
DOIs
Publication statusE-pub ahead of print - 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • grain boundaries
  • graphene
  • magnetism
  • superconductivity
  • topology, Yu–Shiba–Rusinov states

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