2D bilayer chromium pnictogens as a metallic material under DFT investigation through their structural, vibrational, electronic, and elastic properties

Abstract

A comprehensive investigation of the structural, vibrational, electronic, and elastic characteristics of four hexagonal bilayer chromium pnictogens (CrX; X = N, P, As, Sb) materials has been conducted using first-principles calculations based on density functional theory (DFT). The phonon dispersion investigations demonstrate the dynamic stability of the examined hexagonal bilayers belonging to pnictogens group, in their planar structure. According to our phonon dispersion analysis, only two materials, CrN/CrN and CrP/CrP, are found to be dynamically stable, while the other two, CrAs/CrAs and CrSb/CrSb are reveal to be dynamically unstable. The band structure calculations carried out utilizing HSE06 hybrid functionals reveals the metallic nature of bilayer chromium pnictogens. In all CrX materials, the highest work function we observed for CrN/CrN material as 5.17 eV. Along the armchair direction in CrN/CrN compounds, highest elastic constants (C2D) is obtained among all CrX compounds, measured as 192.47 Nm−1 for electron carriers. In addition to examining the phonon dispersion, we also assessed their mechanical stability by the computation of elastic characteristics. Our calculated elastic parameters and polar diagrams of Young's modulus and Poisson's ratio indicate the mechanical stability of all the systems under consideration. To further our understanding of CrX compounds, we also acquired data on their deformation potential for electron carriers in both armchair and zigzag orientations. This work unequivocally demonstrates the advantages of CrX bilayers as potential materials for upcoming robust conducting devices and also possible applications for a 2D metallic material.