Exploring mechanical, electronic, vibrational, and thermoelectric properties of CaGa2P2, CaGa2As2, and SrGa2As2

Abstract

First principles calculations are performed to systematically investigate the electronic, elastic, vibrational, and thermoelectric properties of the hexagonal, rhombohedral and monoclinic structures of CaGa2P2, CaGa2As2, and SrGa2As2 compounds. We adopt the generalized gradient approximation designed by Perdew, Burke, and Ernzerhof (PBE) for the exchange-correlation energy. The obtained structural parameters are agreement with the experimental values. The elastic and phonon properties were derived to discuss their stability in mechanical and dynamical. Mechanical properties were deduced within the Voigt-Reuss-Hill approximation. The brittleness and ductility are estimated by the values of Poisson's ratio and Pugh's rule (B/G). The electronic structures were used to illustrate the band characteristics. Minimum thermal conductivity has calculated and discussed. In addition, the transport properties, such as Seebeck coefficient, thermal conductivity, power factor, and electrical conductivity have been evaluated as function of energy relative to the Fermi level at various temperatures (T). We have also provided conservative estimates of the figure of merit (ZT). Overall, our results suggest potential new candidates of CaGa2P2, CaGa2As2, and SrGa2As2 for high thermoelectric performance.