Ground state parameters, electronic properties and elastic constants of CaMg3: DFT study

Abstract

The present study aims to investigate the equation of state (EOS) parameters of CaMg3 in αReO3 (D09), AlFe3 (D03), Cu3Au (L12) and CuTi3 (L60) structures, using full potential linear muffin-tin orbitals (FP-LMTO) approach based on the density functional theory (DFT). The local density approximation (LDA) and the generalized gradient approximation (GGA) were both applied for the exchange-correlation potential term. The calculated equation of state parameters at equilibrium, in general, agreed well with the available data of the literature. The calculations showed that under compression CaMg3 transforms from D03 to D09 at about 29.96 GPa, and 25.1 GPa using LDA and GGA, respectively.

The elastic constants Cij, aggregate moduli, Vickers hardness, sound velocity, and Debye temperature of CaMg3 in D03 structure were also reported, discussed and analyzed. Using LDA (GGA), the calculated values of HV and θD were found at around 5.80 GPa (5.93 GPa) and 393.44 K (389.91 K), respectively.

Electronic band structure, total density of states (TDOS) as well as the partial density of states (PDOS) have been also obtained. The electronic band structure confirms the metallic behavior of CaMg3 in D03 phase, the valence bands are dominated by the maximum contribution of ‘d’ like states of Ca in the energy ranging from 2 to 3 eV for GGA, and from 4.5 to 5 eV for LDA, respectively.