Computational prediction of novel two-dimensional tungsten nitride superconductors.

Transition metal nitrides are well-known 3D superconductor materials. However, there is a lack of knowledge related to their two-dimensional (2D) counterparts, which have several potential technological applications. In this work, we predict, using an evolutionary algorithm coupled with a first-principles approach, a set of novel 2D superconductive structures based on tungsten nitride.

Band Alignment of the CuGaS Chalcopyrite Interfaces Studied by First-Principles Calculations.

The valence and conduction band offsets for both polar and nonpolar CuGaS/CuAlSe and CuGaS/ZnSe interfaces were studied here by the state-of-the-art first-principles calculations. Using the hybrid functional calculations, we show that the CuGaS/CuAlSe and CuGaS/ZnSe heterostructures in all interfaces form type II band alignment. The difference of valence and conduction band offsets is mainly due to lattice mismatch, generating stress in the interface and affecting the electronic properties of each material; meanwhile, the polarity configuration does not play an important role in these values.