Recent breakthrough in search for the analogs of fundamental particles in condensed matter systems lead to experimental realizations of 3D Dirac and Weyl semimetals. Weyl state can be hosted either by non-centrosymmetric or magnetic materials and can be of the first or the second type. Several non-centrosymmetric materials have been proposed to be type-II Weyl semimetals, but in all of them the Fermi arcs between projections of multiple Weyl points either have not been observed directly or they were hardly distinguishable from the trivial surface states which significantly hinders the practical application of these materials. Here we present experimental evidence for type-II non-centrosymmetric Weyl state in TaIrTe4 where it has been predicted theoretically. We find direct correspondence between ARPES spectra and calculated electronic structure both in the bulk and the surface and clearly observe the exotic surface states which support the quasi-1D Fermi arcs connecting only four Weyl points. Remarkably, these electronic states are spin-polarized in the direction along the arcs, thus highlighting TaIrTe4 as a novel material with promising application potential.
@article{arxiv.1609.09549,
title = {Experimental realization of type-II Weyl state in non-centrosymmetric TaIrTe$_4$},
author = {E. Haubold and K. Koepernik and D. Efremov and S. Khim and A. Fedorov and Y. Kushnirenko and J. van den Brink and S. Wurmehl and B. Buchner and T. K. Kim and M. Hoesch and K. Sumida and K. Taguchi and T. Yoshikawa and A. Kimura and T. Okuda and S. V. Borisenko},
journal= {arXiv preprint arXiv:1609.09549},
year = {2017}
}