Ab‐initio thermodynamic calculations of Mg 2 B IV (B IV = Si, Ge, Sn) solid solutions

The thermodynamic properties of ternary Mg 2 B IV (B IV = Si, Ge, Sn) solid solutions were first calculated by the ab‐initio density functional method. The results showed that there exist composition regions with d 2 G /d x 2 < 0 in Mg 2 Si 1– x Sn x and Mg 2 Ge 1– x Sn x systems, implying the possibility of spinodal decomposition of the pseudobinary solid solutions. It is suggested that the spinodal decomposition would be a potential way to obtain Mg 2 B IV based bulk in‐situ nanocomposites with reduced grain sizes and enhanced phonon scattering, and hence an improved thermoelectric figure of merit. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)