The ferromagnetic phase of the cubic antiperovskite Mn3ZnC is suggested from first-principles calculation to be a nodal line Weyl semimetal. Features in the electronic structure that are the hallmark of a nodal line Weyl state, a large density of linear band crossings near the Fermi level, can also be interpreted as signatures of a structural and/or magnetic instability. Indeed, it is known that Mn3ZnC undergoes transitions upon cooling from a paramagnetic to a cubic ferromagnetic state under ambient conditions and then further into a non-collinear ferrimagnetic tetragonal phase at a temperature between 250K and 200K. The existence of Weyl nodes and their destruction via structural and magnetic ordering is likely to be relevant to a range of magnetostructurally coupled materials.
@article{arxiv.1910.00184,
title = {Weyl nodes and magnetostructural instability in antiperovskite Mn$_3$ZnC},
author = {Samuel M. L. Teicher and Ida K. Svenningsson and Leslie M. Schoop and Ram Seshadri},
journal= {arXiv preprint arXiv:1910.00184},
year = {2019}
}