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Cornils L, Kamlapure A, Zhou L, Pradhan S, Khajetoorians AA, Fransson J, Wiebe J, Wiesendanger R. Spin-Resolved Spectroscopy of the Yu-Shiba-Rusinov States of Individual Atoms. Phys Rev Lett 2017; 119:197002. [PMID: 29219531 DOI: 10.1103/physrevlett.119.197002] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Indexed: 06/07/2023]
Abstract
A magnetic atom in a superconducting host induces so-called Yu-Shiba-Rusinov (YSR) bound states inside the superconducting energy gap. By combining spin-resolved scanning tunneling spectroscopy with simulations we demonstrate that the pair of peaks associated with the YSR states of an individual Fe atom coupled to an oxygen-reconstructed Ta surface gets spin polarized in an external magnetic field. As theoretically predicted, the electron and hole parts of the YSR states have opposite signs of spin polarizations which keep their spin character when crossing the Fermi level through the quantum phase transition. The simulation of a YSR state right at the Fermi level reveals zero spin polarization which can be used to distinguish such states from Majorana zero modes in chains of YSR atoms.
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Affiliation(s)
- L Cornils
- Department of Physics, Hamburg University, D-20355 Hamburg, Germany
| | - A Kamlapure
- Department of Physics, Hamburg University, D-20355 Hamburg, Germany
| | - L Zhou
- Department of Physics, Hamburg University, D-20355 Hamburg, Germany
| | - S Pradhan
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, Uppsala SE-751 21, Sweden
| | | | - J Fransson
- Department of Physics and Astronomy, Uppsala University, P.O. Box 516, Uppsala SE-751 21, Sweden
| | - J Wiebe
- Department of Physics, Hamburg University, D-20355 Hamburg, Germany
| | - R Wiesendanger
- Department of Physics, Hamburg University, D-20355 Hamburg, Germany
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Manna S, Kamlapure A, Cornils L, Hänke T, Hedegaard EMJ, Bremholm M, Iversen BB, Hofmann P, Wiebe J, Wiesendanger R. Interfacial superconductivity in a bi-collinear antiferromagnetically ordered FeTe monolayer on a topological insulator. Nat Commun 2017; 8:14074. [PMID: 28094258 PMCID: PMC5247605 DOI: 10.1038/ncomms14074] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/25/2016] [Indexed: 11/09/2022] Open
Abstract
The discovery of high-temperature superconductivity in Fe-based compounds triggered numerous investigations on the interplay between superconductivity and magnetism, and on the enhancement of transition temperatures through interface effects. It is widely believed that the emergence of optimal superconductivity is intimately linked to the suppression of long-range antiferromagnetic (AFM) order, although the exact microscopic picture remains elusive because of the lack of atomically resolved data. Here we present spin-polarized scanning tunnelling spectroscopy of ultrathin FeTe1-xSex (x=0, 0.5) films on bulk topological insulators. Surprisingly, we find an energy gap at the Fermi level, indicating superconducting correlations up to Tc∼6 K for one unit cell FeTe grown on Bi2Te3, in contrast to the non-superconducting bulk FeTe. The gap spatially coexists with bi-collinear AFM order. This finding opens perspectives for theoretical studies of competing orders in Fe-based superconductors and for experimental investigations of exotic phases in superconducting layers on topological insulators.
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Affiliation(s)
- S Manna
- Department of Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
| | - A Kamlapure
- Department of Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
| | - L Cornils
- Department of Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
| | - T Hänke
- Department of Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
| | - E M J Hedegaard
- Department of Chemistry and iNANO, Center for Materials Crystallography, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - M Bremholm
- Department of Chemistry and iNANO, Center for Materials Crystallography, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - B B Iversen
- Department of Chemistry and iNANO, Center for Materials Crystallography, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Ph Hofmann
- Department of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, DK-8000 Aarhus C, Denmark
| | - J Wiebe
- Department of Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
| | - R Wiesendanger
- Department of Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany
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