Interaction effects in a two-dimensional AlSi[formula omitted]P nanosheet: A first-principles study on the electronic, mechanical, thermal, and optical properties

Abstract

Physical quantities such as the electronic, the mechanical, the thermal, and the optical properties of Al and P codoped silicene forming AlSi6P nanosheets are investigated by first-principle calculations within density functional theory. A particular attention of this study is paid to the interaction effect between the Al and the P atoms in the buckled silicene structure. We infer that the interaction type is attractive and it leads to an asymmetry in the density of states opening up a band gap. In contrast to BN-codoped silicene, the buckling in the Al–P codoped silicene is not much influenced by the dopants as the bond lengths of Si–P and Al–P are very similar to the Si–Si bond lengths. On the other hand, the longer bond length of Si–Al decreases the stiffness and thus induces fractures at smaller values of applied strain in AlSi6P. The elastic and the nonelastic regions of the stress–strain curve of AlSi6P depend on the placement of the Al and the P atoms. The finite band gap caused by the Al–P dopant leads to enhancement of the Seebeck coefficient and the figure of merit, and induces a redshift of peaks in the dielectric response, and the optical conductivity. Finally, properties of the real and the imaginary parts of the dielectric function, the excitation spectra, the refractive index, and the optical response of AlSi6P are reported.