New possible structure of silicide Mg$_{2}$Si under pressure

As a result of an evolutionary search based on the density functional theory, a new low-symmetry structure of silicide Mg$_{2}$Si under pressure was discovered. This structure can exist along with the known structures of the symmetry Pnma and P63/mmc and is stable at a pressure of about 20 GPa. The lattice parameters of the discovered structure are in better agreement with the experimental values than the lattice parameters of the known structures.