Topological properties of Mo2C and W2C superconductors

The topological electronic properties of orthorhombic-phase Mo2C and W2C superconductors have been studied based on first-principles electronic structure calculations. Our studies show that both Mo2C and W2C are three-dimensional strong topological insulators defined on curved Fermi levels. The topological surface states on the (001) surface of Mo2C right cross the Fermi level, while those of W2C pass through the Fermi level with slight electron doping. These surface states hold helical spin textures and can be induced to become superconducting via a proximity effect, giving rise to an equivalent p + ip type superconductivity. Our results show that Mo2C and W2C can provide a promising platform for exploring topological superconductivity and Majorana zero modes.