Magnesium based tin-silicon alloys under pressure: first-principles evolution search results

The search of minimal enthalpy structures of ternary magnesium alloys of different stoichiometry Mg$_x$Si$_y$Sn$_z$ under pressure $P\le$6 GPa has been performed using the software suite USPEX implementing the evolution algorithm combined with the density functional theory (DFT) approach. The evolutionary search has yielded new possible ternary compounds of the stoichiometries Mg$_{12}$Si$_3$Sn, Mg$_4$SiSn and Mg$_6$Si$_3$Sn, which have negative enthalpy of formation at pressures in the range of 0 to 10 GPa and which are not substitution solutions. These compounds have metallic properties and formation energies comparable to those of binary silicides Mg$_x$Si$_y$.