Doping-induced changes in the structural and mechanical properties of germanene monolayers: A DFT-Based study

Abstract

In the current study, the density functional theory is utilized to investigate the elastic, plastic and electronic properties of the 2×2 and 3×3 pristine and transition metal (TM) doped germanene. Different atoms, including V, Co, Fe, Mn, Cr, Ti, Ni and Sc are selected for this purpose. It is shown that doping of the transition metal atoms would result in the reduction of the Young's and bulk moduli of the germanene. In addition, the isotropic behavior of these nanosheets were shown by comparing the Young's moduli of both pristine and doped structures in armchair and zigzag directions. Furthermore, the plastic behavior of these structures were investigated by increasing the applied loading. It was seen that except for the 2×2 Co-doped monolayer, the yield strain of both 2×2 and 3×3 nanosheets were reduced under uniaxial and biaxial loading. In 2×2 doped nanosheets under uniaxial loading, the highest reduction occurs for Ti-doped germanene, and in 3×3 cases, the highest reduction happens for Co, Ni, Fe and Sc-doped germanene. Electron localization function revealed the ionic nature of the boding between TM atoms and germanium while the density of state indicated that doping of transition metals would change the semi-metallic behavior of germanene to metallic except for Ti-doped structure. The findings provide valuable information for potential applications in nanotechnology, guiding the development of new materials with specific characteristics based on the identified impacts of different transition metals.