Mapping the orbital structure of impurity bound states in a superconductor

Deung Jang Choi, Carmen Rubio-Verdú, Joeri De Bruijckere, Miguel M. Ugeda, Nicolás Lorente, Jose Ignacio Pascual

Research output: Contribution to journalArticleScientificpeer-review

40 Citations (Scopus)
24 Downloads (Pure)

Abstract

A magnetic atom inside a superconductor locally distorts superconductivity. It scatters Cooper pairs as a potential with broken time-reversal symmetry, leading to localized bound states with subgap excitation energies, named Shiba states. Most conventional approaches regarding Shiba states treat magnetic impurities as point scatterers with isotropic exchange interaction. Here, we show that the number and the shape of Shiba states are correlated to the spin-polarized atomic orbitals of the impurity, hybridized with the superconductor. Using scanning tunnelling spectroscopy, we spatially map the five Shiba excitations found on subsurface chromium atoms in Pb(111), resolving their particle and hole components. While particle components resemble d orbitals of embedded Cr atoms, hole components differ strongly from them. Density functional theory simulations correlate the orbital shapes to the magnetic ground state of the atom, and identify scattering channels and interactions, all valuable tools for designing atomic-scale superconducting devices.

Original languageEnglish
Article number15175
Number of pages6
JournalNature Communications
Volume8
DOIs
Publication statusPublished - 2017

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