Topological superconductivity in Ni-based transition metal trichalcogenides

Based on a two-orbital honeycomb lattice model and by use of a random phase approximation analysis we investigate the pairing symmetry of Ni-based transition metal trichalcogenides. We find that an I-wave (A2g) state and a chiral d-wave (Eg) state are dominant and nearly degenerate for typical electron and hole dopings. Both pairing states exhibit nontrivial topological properties, which manifest themselves by the chiral edge states for the d+id-wave state and dispersionless Andreev bound state at zero energy for the I-wave state. We thus show that Ni-based transition metal trichalcogenides provide a promising platform to study exotic topological phenomena emerging from electronic correlation effects.