To further study the electronic band structure of triclinic NbSe 2 I 2 , we employed the VASP 5.4 PBE projector-augmented wave (PAW) pseudo-potentials and the optB88-vdW functions for band structure calculations, for both bulk and mono-layer structures, shown in For both bulk and mono-layer structures, there is an isolated band at around -0.5 eV, corresponding to the 4d band of niobium. The electronic band structures of bulk monoclinic (C2/m) NbSe 2 I 2 were also calculated, shown in Figure in Supporting Information, and the monoclinic and triclinic phases share the same general features.