Imaging the real space structure of the spin fluctuations in an iron-based superconductor

Shun Chi; Ramakrishna Aluru; Stephanie Grothe; A Kreisel; Udai Raj Singh; Brian M Andersen; W N Hardy; Ruixing Liang; D A Bonn; S A Burke; Peter Wahl

doi:10.1038/ncomms15996

Imaging the real space structure of the spin fluctuations in an iron-based superconductor

Nat Commun. 2017 Jun 29:8:15996. doi: 10.1038/ncomms15996.

Authors

Shun Chi^{1

2}, Ramakrishna Aluru^{3

4}, Stephanie Grothe^{1

2}, A Kreisel^{5

6}, Udai Raj Singh⁴, Brian M Andersen⁵, W N Hardy^{1

2}, Ruixing Liang^{1

2}, D A Bonn^{1

2}, S A Burke^{1

2

7}, Peter Wahl^{3

4}

Affiliations

¹ Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1.
² Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
³ SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS, UK.
⁴ Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, D-70569 Stuttgart, Germany.
⁵ Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark.
⁶ Institut für Theoretische Physik, Universität Leipzig, D-04103 Leipzig, Germany.
⁷ Department of Chemistry, University of British Columbia, Vancouver British Columbia, Canada V6T 1Z1.

Abstract

Spin fluctuations are a leading candidate for the pairing mechanism in high temperature superconductors, supported by the common appearance of a distinct resonance in the spin susceptibility across the cuprates, iron-based superconductors and many heavy fermion materials. The information we have about the spin resonance comes almost exclusively from neutron scattering. Here we demonstrate that by using low-temperature scanning tunnelling microscopy and spectroscopy we can characterize the spin resonance in real space. We show that inelastic tunnelling leads to the characteristic dip-hump feature seen in tunnelling spectra in high temperature superconductors and that this feature arises from excitations of the spin fluctuations. Spatial mapping of this feature near defects allows us to probe non-local properties of the spin susceptibility and to image its real space structure.

Publication types

Research Support, Non-U.S. Gov't