LAUSR

Abstract An expanding enthusiasm for Dirac Semimetals is because of their intriguing properties identical to that of graphene. An insight evaluation of structural, electronic and mechanical properties of Ca3PbO and Ca3SnO has been made within the framework of Density Functional Theory (DFT). The semi classical Boltzmann transport hypothesis has been utilized to process thermoelectric properties and vibrational properties have been determined by applying Density Functional Perturbation Theory (DFPT). The theoretical computation of thermoelectric and phononic properties has been made for the first time. The computation of electronic band structure shows linear band dispersion at Fermi level along the line adjoining Г and X points in momentum space, specifying Ca3PbO and Ca3SnO to be Dirac Semimetals with band gap of 21 meV and 9 meV respectively. The smaller band gap of Ca3SnO results in enhanced carrier mobility and is intended to be better for mutlivalley electronics. The fulfillment of Born-Haung stability criteria by the computed elastic constants validate the mechanical stability, uncovering the anisotropic and purely covalent bonding of both Ca3PbO and Ca3SnO. The present study draws conclusion that Ca3SnO is finer thermoelectric material than Ca3PbO over wide temperature range from 50 K to 800 K. Ca3SnO exhibits best figure of merit of 0.1371 at 600 K while Ca3PbO displays best figure of merit of 0.107 at 550 K. Room temperature lattice thermal conductivity has been determined to be 1.23 W/mK and 1.63 W/mK for Ca3PbO and Ca3SnO respectively. As far as the stability of the crystal is concerned, it is clearly stated by the calculated positive phonon frequencies. The estimation of dielectric consistent has been assessed to be 12.74 for Ca3PbO and 11.71 for Ca3SnO. The amount of Born effective charge transfer is more in Ca3SnO in contrast to Ca3PbO. The outcomes of current study are in fair accordance with available experimental and theoretical results. The present computational assessment tends to stimulate further experimental research for the implementation of Ca3PbO and Ca3SnO in most recent innovative applications.