Time-reversal symmetry breaking in the Fe-chalcogenide superconductors
- 12 January 2021
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 118 (3)
- https://doi.org/10.1073/pnas.2007241118
Abstract
Topological superconductivity has been sought in a variety of heterostructure systems, the interest being that a material displaying such a phenomenon could prove to be the ideal platform to support Majorana fermions, which in turn could be the basis for advanced qubit technologies. Recently, the high-Tc family of superconductors, FeTe1−xSex, have been shown to exhibit the property of topological superconductivity and further, evidence has been found for the presence of Majorana fermions. We have studied the interplay of topology, magnetism, and superconductivity in the FeTe1−xSex family using high-resolution laser-based photoemission. At the bulk superconducting transition, a gap opens at the chemical potential as expected. However, a second gap is observed to open at the Dirac point in the topological surface state. The associated mass acquisition in the topological state points to time-reversal symmetry breaking, probably associated with the formation of ferromagnetism in the surface layer. The presence of intrinsic ferromagnetism combined with strong spin–orbit coupling provides an ideal platform for a range of exotic topological phenomena.Funding Information
- U.S. Department of Energy (DE-AC02-98CH10886)
- U.S. Department of Energy (DE-AC02-98CH10886)
- U.S. Department of Energy (DE-AC02-98CH10886)
- U.S. Department of Energy (DE-AC02-98CH10886)
- DOD | USAF | AFMC | Air Force Office of Scientific Research (FA9550-14-1-0168.)
This publication has 19 references indexed in Scilit:
- Discovery of orbital-selective Cooper pairing in FeSeScience, 2017
- Tuning across the BCS-BEC crossover in the multiband superconductor Fe
1+
y
Se
x
Te
1−
x
: An angle-resolved photoemission studyScience Advances, 2017
- Giant superconducting fluctuations in the compensated semimetal FeSe at the BCS–BEC crossoverNature Communications, 2016
- Evidence for orbital order and its relation to superconductivity in FeSe 0.4 Te 0.6Science Advances, 2015
- Spin-Orbit Interactions and the Nematicity Observed in the Fe-Based SuperconductorsPhysical Review Letters, 2015
- From quantum matter to high-temperature superconductivity in copper oxidesNature, 2015
- Anisotropic vortex lattice structures in the FeSe superconductorPhysical Review B, 2012
- Isotropic superconducting gaps with enhanced pairing on electron Fermi surfaces in FeTeSePhysical Review B, 2012
- Massive Dirac Fermion on the Surface of a Magnetically Doped Topological InsulatorScience, 2010
- Nodal quasiparticle lifetimes in cuprate superconductorsPhysical Review B, 2005