First-principles calculations of electronic structure and optical and elastic properties of the novel ABX₃-type LaWN₃...

The development of ABX₃-type advanced perovskite materials has become a focus for both scientific researchers and the material genome initiative (MGI). In addition to the traditional perovskite ABO₃ and halide perovskite ABX₃, LaWN₃ is discovered as a new ABX₃-type advanced perovskite structure. The elastic and optical properties of this novel LaWN₃ structure are systematically studied via DFT. Based on the calculated elastic constants, the bulk modulus, shear modulus, Young's modulus and Pugh modulus ratio are precisely obtained. Results show that (1) LaWN₃ is an indirect bandgap semiconductor with a hybrid occuring near the Fermi level and the main contributions are La-d, W-d and N-p. (2) LaWN₃ has a certain ductility. The optical constants, such as absorption spectrum, energy-loss spectrum, conductivity, dielectric function, reflectivity and refractive index, are analyzed and the static dielectric constant is 10.98 and the refractivity index is 3.31. (3) The optical constants of LaWN₃ are higher than those of other existing ABX₃-type materials, showing very promising application as a functional perovskite in the future. The existence of this stable LaWN₃ structure might widen the perovskite material's application, such as in photodetectors, light-emitting diodes, perovskite solar cells, fuel cells and so on.