First-principle investigations on the structural dynamics of Ti2GaN

We report a first-principle study on the elastic and electronic properties of the nanolaminate Ti2GaN. Our calculated lattice parameter shows that c axis is always stiffer than a axis. The elastic constants investigations demonstrated that Ti2GaN is stable over a wide pressure range of 0-1000 GPa with the only exception of 350-600 GPa owing to the elastic softening. The softening behaviors of the Young's and shear moduli are also found in the same pressure range of 350-600 GPa, indicating a structural metastability. Investigation on the axial compressibility we observed an abnormal c-axis expansion behavior within a pressure range of 350-600 GPa, resulting from the expansion of the Ti-Ti bond length and the increase of the Ti-Ti bond population. Study on the density of states (DOSs) we found that the Ti s and Ti p electrons shift towards higher energies with pressure.