Dirac nodal arc in 1T-VSe2

Transition metal dichalcogenides are hosts to interesting electronic order states intertwined with non-trivial band topology. Here, systematic photoemission experiments on 1T-VSe2 reveal a Dirac nodal arc emerging from band inversion and supporting spin-momentum locked topological surface states. Transition metal dichalcogenides exhibit many fascinating properties including superconductivity, magnetic orders, and charge density wave. The combination of these features with a non-trivial band topology opens the possibility of additional exotic states such as Majorana fermions and quantum anomalous Hall effect. Here, we report on photon-energy and polarization dependent spin-resolved angle-resolved photoemission spectroscopy experiments on single crystal 1T-VSe2, revealing an unexpected band inversion and emergent Dirac nodal arc with spin-momentum locking. Density functional theory calculations suggest a surface lattice strain could be the driving mechanism for the topologically nontrivial electronic structure of 1T-VSe2.