In metallic condensed matter systems two different types of Weyl fermions can in principle emerge, with either a vanishing (type-I) or with a finite (type-II) density of states at the Weyl node energy. So far only WTe2 and MoTe2 were predicted to be type-II Weyl semi-metals. Here we identify TaIrTe4 as a third member of this family of topological semi-metals. TaIrTe4 has the attractive feature that it hosts only four well-separated Weyl points, the minimum imposed by symmetry. Moreover, the resulting topological surface states - Fermi arcs connecting Weyl nodes of opposite chirality - extend to about 1/3 of the surface Brillouin zone. This large momentum-space separation is very favorable for detecting the Fermi arcs spectroscopically and in transport experiments.
@article{arxiv.1603.04323,
title = {TaIrTe4 a ternary Type-II Weyl semi-metal},
author = {K. Koepernik and D. Kasinathan and D. V. Efremov and Seunghyun Khim and Sergey Borisenko and Bernd Büchner and Jeroen van den Brink},
journal= {arXiv preprint arXiv:1603.04323},
year = {2016}
}