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

Niels B.M. Schröter, Iñigo Robredo, Sebastian Klemenz, Robert J. Kirby, Jonas A. Krieger, Ding Pei, Tianlun Yu, Samuel Stolz, Thorsten Schmitt, Pavel Dudin, Timur K. Kim, Cephise Cacho, Andreas Schnyder, Aitor Bergara, Vladimir N. Strocov, Fernando de Juan, Maia G. Vergniory, Leslie M. Schoop

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish (US)
Article numbereabd5000
JournalScience Advances
Volume6
Issue number51
DOIs
StatePublished - Dec 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General

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