Weyl fermions, Fermi arcs, and minority-spin carriers in ferromagnetic CoS2

DOI: 10.1126/sciadv.abd5000

Authors: Niels B. M. Schroeter (Swiss Light Source) , Iñigo Robredo (Donostia International Physics Center; University of the Basque Country UPV/EHU) , Sebastian Klemenz (Princeton University) , Robert J. Kirby (Princeton University) , Jonas A. Krieger (Swiss Light Source; ETH Zurich; Paul Scherrer Institute) , Ding Pei (University of Oxford) , Tianlun Yu (Swiss Light Source; Fudan University) , Samuel Stolz (EMPA, Swiss Federal Laboratories for Materials Science and Technology; EPFL) , Thorsten Schmitt (Swiss Light Source) , Pavel Dudin (Diamond Light Source) , Timur K. Kim (Diamond Light Source) , Cephise Cacho (Diamond Light Source) , Andreas Schnyder (Max Planck Institute for Solid State Research) , Aitor Bergara (Donostia International Physics Center; University of the Basque Country UPV/EHU; Centro Mixto CSIC -UPV/EHU) , Vladimir N. Strocov (Swiss Light Source) , Fernando De Juan (Donostia International Physics Center; IKERBASQUE, Basque Foundation for Science) , Maia G. Vergniory (Donostia International Physics Center; IKERBASQUE, Basque Foundation for Science) , Leslie M. Schoop (University of the Basque Country UPV/EHU)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Science Advances , VOL 6

State: Published (Approved)
Published: December 2020
Diamond Proposal Number(s): 26098 , 20617

Abstract: Magnetic Weyl semimetals are a newly discovered class of topological materials that may serve as a platform for exotic phenomena, such as axion insulators or the quantum anomalous Hall effect. Here, we use angle-resolved photoelectron spectroscopy and ab initio calculations to discover Weyl cones in CoS2, a ferromagnet with pyrite structure that has been long studied as a candidate for half-metallicity, which makes it an attractive material for spintronic devices. We directly observe the topological Fermi arc surface states that link the Weyl nodes, which will influence the performance of CoS2 as a spin injector by modifying its spin polarization at interfaces. In addition, we directly observe a minority-spin bulk electron pocket in the corner of the Brillouin zone, which proves that CoS2 cannot be a true half-metal.

Diamond Keywords: Spintronics; Ferromagnetism

Subject Areas: Materials, Physics


Instruments: I05-ARPES

Added On: 04/01/2021 14:20

Documents:
eabd5000.full.pdf

Discipline Tags:

Quantum Materials Hard condensed matter - electronic properties Physics Electronics Magnetism Materials Science

Technical Tags:

Spectroscopy Angle Resolved Photoemission Spectroscopy (ARPES) High Resolution ARPES (HR-ARPES)