Ab initio study of the chemical bonding and mechanical properties of Li₂SiZn

Using ab initio calculations, we have investigated the chemical bonding and elastic properties of Li₂SiZn (space groups P6₂/mmc and P3̄ml). Both structures have been observed experimentally. These compounds exhibit a layered structure where Li-Zn layers are interleaved with Si layers. The most dominant chemical bonding is ionic, and the bulk moduli calculated are 42 and 22 GPa, respectively. While the layered nature thereof is similar to the so-called MAX phases (where M=transition metal, A=group element, and X=C or N [M. W. Barsoum, Prog. Solid State Chem. 28, 201 (2000)], the elastic properties are rather different. This can be understood by analyzing the differences in chemical bonding between Li₂SiZn and MAX phases. It is our ambition that these calculations may inspire future research on the Li₂SiZn phases.