Using spin- and angle- resolved photoemission spectroscopy (spin-ARPES) together with abinitio calculations, we demonstrate the existence of a type-II Dirac semimetal state in NiTe2. We show that, unlike PtTe2, PtSe2, and PdTe2, the Dirac node in NiTe2 is located in close vicinity of the Fermi energy. Additionally, NiTe2 also hosts a pair of band inversions below the Fermi level along the Γ−A high-symmetry direction, with one of them leading to a Dirac cone in the surface states. The bulk Dirac nodes and the ladder of band inversions in NiTe2 support unique topological surface states with chiral spin texture over a wide range of energies. Our work paves the way for the exploitation of the low-energy type-II Dirac fermions in NiTe2 in the fields of spintronics, THz plasmonics and ultrafast optoelectronics.
@article{arxiv.1908.04099,
title = {Low-energy type-II Dirac fermions and spin-polarized topological surface states in transition-metal dichalcogenide NiTe$_2$},
author = {Barun Ghosh and Debashis Mondal and Chia-Nung Kuo and Chin Shan Lue and Jayita Nayak and Jun Fujii and Ivana Vobornik and Antonio Politano and Amit Agarwal},
journal= {arXiv preprint arXiv:1908.04099},
year = {2019}
}