The magnetic analogs of ZrSiS-type materials

ZrSiS and related materials have been widely studied because they (a) feature a 3D Dirac line node at the Fermi level and (b)
exhibit 4fold degeneracies that are protected by non-symmorprhic symmetry below or at the Fermi level [1,2]. In this talk we will
discuss the magnetic analog CeSbTe, and show how magnetism affects the electronic structure [3]. We will show that we can achieve both,
antiferromagnetic and ferromagnetic order in this material, and that depending on the magnetic structure different topological features can be accessed. Importantly, we will show that antiferromagnetic order can add non-symmorphic symmetry elements and thus create 8fold degeneracies that have been associated with new fermions [4]. This extends the number of possible space groups where 8fold degeneracies can be found. We will also discuss the stability limits of the square net structure for different rare earth cations.

[1] Schoop, L.M., et. al, 2016. Nat. comm., 7.
[2] Q. Xu, et. al, 2015 Physical Review B 92, 205310.
[3] Schoop, L.M.et al, 2017. arXiv:1707.03408.
[4] Bradlyn, et. al, 2016. Science, p.aaf5037