Elastic properties and Debye Temperature of Tetragonal and Cubic Ga_3Zr Under High Pressure: A First-Principles Investigation

摘要

Two different phases of Ga_3Zr with tetragonal (D0_(22)) and cubic (L1_2) structures under high pressure are investigated by using density functional theory (DFT) calculations. The elastic constants (C_(ij)) and mechanical moduli, including bulk modulus (B) and shear modulus (G), are calculated under various pressures. When pressure goes up, the increasing tendency of C_(ij), B and G are confirmed. On the basis of Pugh's criterion, L1_2-Ga_3Zr has better ductility comparing with D0_(22)-Ga_3Zr under various pressures in the range of 0～60 GPa. The brittleness of D0_(22)-Ga_3Zr depends on the pressure, it will become ductile when the pressure rise up higher than ～35 GPa. For the both phases, Debye temperature (Θ_D) is also calculated under high pressures. For the both phases, Debye temperature increases with pressure rising up. Under pressures ranging from 0 GPa to 60 GPa, the Θ_D values of L1_2-Ga_3Zr are lower than the ones of D0_(22)-Ga_3Zr.