A DFT investigation on the mechanical and structural properties of silicene nanosheets under doping of transition metals

Abstract

In this paper, the elastic and plastic properties of 2 × 2 and 3 × 3 pristine and transition metal (TM) doped silicene nanosheets are studied using the density functional theory (DFT) calculations. Cr, Co, Cu, Mn, Ti, V, Zn and Ni atoms are selected as doping atoms. It is observed that Young’s and bulk moduli of both 2 × 2 and 3 × 3 pristine structures decrease when they are affected by the doping atoms. The highest reduction in the Young’s and bulk moduli of the 2 × 2 nanosheets occurs for the Ni-doped structure, and the same reduction is observed for the Ni- and Cu-doped structures in the 3 × 3 nanosheets. In addition, it is shown that all of the investigated structures have an isotropic behavior, since their Young’s moduli have negligible difference along armchair and zigzag directions. Finally, the loading is further increased to investigate the plastic behavior of nanostructures. The results show that the yield strains of all doped nanosheets decrease under uniaxial and biaxial loadings. The highest reduction in the yield strain of the 2 × 2 nanosheets under biaxial loading is observed for Cu, Zn- and Co-doped nanosheets, and in 3 × 3 nanosheets, the highest reduction happens for the Cu- and Zn-doped nanosheets under the same condition. For the yield strain of the 2 × 2 doped nanosheets under the uniaxial loading, the Cu-doped structure experiences the highest reduction, and the highest reduction for the Mn-doped nanosheet under the same condition is observed in 3 × 3 nanosheets. The findings revealed that how electronic configuration of transition metal atom and its electronegativity difference with silicon atom can control the structural and mechanical properties of the nanosheet. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.