Mechanical and electronic properties of single-layer TiN and AlN under strain

Abstract

Recent experimental advances for the fabrication of various two dimensional materials introduced new structures with a wide prospect of applications. In this work, under in-plane uniaxial/biaxial strain, we employed first-principles density functional theory calculations to investigate the mechanical and electronic properties of Aluminum Nitride (AlN) and Titanium Nitride (TiN) sheets. In mechanical section, we obtained second order elastic constants based on directional deformation applied on the structures. Based on the results of our modelling, TiN and AlN layers depending on the atomic configurations and the strain direction can yield remarkable elastic modulus in the range of 137.64 GPa nm for Young's module and high ultimate tensile strength from 6.29 N/m to around 18.34 N/m. In electronic section, by analyzing electronic band structure we observed the band gap variation in terms of strains, especially for AlN. It has 2.93 eV band gap in equilibrium condition, while shows 3.22 eV gap at −8% of uniaxial strain along x direction as the highest amount of originated gap. Despite metallic character of TiN, applying directional strain based on deformation matrices, creates a band gap in specific region of Brillouin zone.