Exploring the potential of 1T-Phase AsX 2 (X=S and Se) monolayers for nanodevice applications: A DFT study

Following the discovery and characterization of dichalcogenide monolayers, which have garnered significant interest in recent years, it is natural to explore new monolayer possibilities for nanodevice applications. The present investigation is aimed at analyzing the structural, vibrational, electronic, and optical properties of 1T-phase arsenic dichalcogenide (AsX 2 ; Formula: see text, and Se) monolayers with the help of the density functional theory (DFT). The Optimized structure lattice constant for AsS 2 and AsSe 2 is 3.48Formula: see textÅand 3.65Formula: see textÅ, respectively. The stability of these materials was confirmed through phonon dispersion analysis and calculations of formation energy. The non-existence of negative value frequencies in the phonon dispersion curve, and with the formation energy of Formula: see text Formula: see texteV and Formula: see text Formula: see texteV for AsS 2 and AsSe 2 , respectively, indicates the dynamical stability of materials. We employed the hybrid exchange-correlation functional HSE06 for calculating the bandgap energy, which reveals the metallic behaviour of both materials. Mechanical stability criteria are satisfied by the values of elastic constant with Young’s modulus values of 61.19Formula: see textN/m and 35Formula: see textN/m, and Poisson’s ratios of 0.3197 and 0.5751 for AsS 2 and AsSe 2 , respectively. Optical properties reveal that the static refractive index values are 2.17 at 3.02Formula: see texteV for AsS 2 and 2.52 at 0.28Formula: see texteV for AsSe 2 . The primary absorption peaks appear at 6.04Formula: see texteV with Formula: see text Formula: see textcmFormula: see text for AsS 2 and at 5.46Formula: see texteV with Formula: see text Formula: see textcmFormula: see text for AsSe 2 . Both monolayers exhibit strong absorption in the ultra-violet (UV) region, these results indicate that the hexagonal 1T-phase AsS 2 and AsSe 2 structures could potentially be synthesized, opening up new possibilities for technological applications.