Comparative study of homoepitaxial Au (111) and Ag (111) layers: Insights from DFT simulations

Abstract

Density Functional Theory (DFT) was employed for the first time in the investigation of Single-layer Nano islands on Ag (111) and Au (111) substrates. This study entailed performing first-principles calculations to assess their electronic and optical characteristics using the ab-initio approach with the full potential linearized augmented plane wave method. The results suggest that Single-layer Nano islands on Ag (111) and Au (111) surfaces exhibit considerable possibility for a range of technical uses, Due to their distinct chemical traits and metallic aspects, such as electrical conductivity. A systematic and comprehensive examination of these structures provides insights into their properties, enabling the exploration of new configurations for technological requirements. In this research paper, we offer a comprehensive analysis of the structural, electronic, and optical features of the newly projected Single-layer Nano islands on Ag (111) and Au (111) surfaces. We compare our findings with first-principles density functional theory. Additionally, we investigate the density of states in the material to figure out the atomic and orbital causes of electronic states. The analysis of the band structure and electronic properties reveals that the valence and conduction bands are predominantly influenced by Ag (111)/Ag (111)–s, Ag (111)/Ag (111)–d orbitals and Ag (111)/Ag (111)–p, Au (111)/Au (111)–p orbitals, respectively around the Fermi level. The Fermi surfaces of two distinct materials are characterized by the presence of three sheets, each populated by both electron and hole states. To investigate the bonding characteristics of these materials, an examination of electronic charge density within the (111) crystallographic planes is undertaken. This analysis reveals the presence of covalent bonding between Ag-Ag and Au-Au atoms. By looking at the dielectric function and associated optical features, such as conductivity, extinction coefficient, refractive index, energy loss function, and reflectivity throughout an energy range of 0 to 14 eV, optical properties are calculated. These materials may be suitable for use in optoelectronic devices, according to research into their optical properties.