Eur. Phys. J. B (2018) 91: 213
https://doi.org/10.1140/epjb/e2018-90302-7

Regular Article

On the possibility of magnetic Weyl fermions in non-symmorphic compound PtFeSb^★

¹ Donostia International Physics Center, P. Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain
² IKERBASQUE, Basque Foundation for Science, Maria Diaz de Haro 3, 48013 Bilbao, Spain
³ Department of Applied Physics II, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
⁴ Condensed Matter Physics Department, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Apdo. 644, 48080 Bilbao, Spain
⁵ ISIS Neutron Pulsed Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Oxford OX11 0QX, UK
⁶ Universität Stuttgart, Institut für Materialwissenschaft - Chemische Materialsynthese, Heisenbergstr. 3, 70569 Stuttgart, Germany
⁷ Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
⁸ Max-Planck-Institut für Festkörperforschung, Heisenbergstr. 1, 70569 Stuttgart, Germany
⁹ Department of Chemistry, Princeton University, Princeton, NJ 08540, USA

^a e-mail: maiagv@gmail.com

Received: 30 April 2018
Received in final form: 25 June 2018
Published online: 1 October 2018

Abstract

Weyl fermions are expected to exhibit exotic physical properties such as the chiral anomaly, large negative magnetoresistance or Fermi arcs. Recently a new platform to realize these fermions has been introduced based on the appearance of a three-fold band crossing at high symmetry points of certain space groups. These band crossings are composed of two linearly dispersed bands that are topologically protected by a Chern number, and a flat band with no topological charge. In this paper, we present a new way of inducing two kinds of Weyl fermions, based on two- and three-fold band crossings, in the non-symmorphic magnetic material PtFeSb. By means of density functional theory calculations and group theory analysis, we show that magnetic order can split a six-fold degeneracy enforced by non-symmoprhic symmetry to create three- or two-fold degenerate Weyl nodes. We also report on the synthesis of a related phase potentially containing two-fold degenerate magnetic Weyl points and extend our group theory analysis to that phase. This is the first study showing that magnetic ordering has the potential to generate new three-fold degenerate Weyl nodes, advancing the understanding of magnetic interactions in topological materials.