We predict NiTe 2 to be a type-II Dirac semimetal based on ab initio calculations and explore its bulk and spin-polarized surface states using spin-and angle-resolved photoemission spectroscopy (spin-ARPES). Our results show that, unlike PtTe 2, PtSe 2, and PdTe 2, the Dirac node in NiTe 2 is located in close vicinity to the Fermi energy. Additionally, NiTe 2 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 NiTe 2 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 NiTe 2 in the fields of spintronics, infrared plasmonics, and ultrafast optoelectronics.
American Physical Society
20 Nov 2019
Volume: 100 Issue: 19 Pages: 195134
Physical Review B