Ba2MNO6 (M = Y, Sc; N = Nb, V, Ta) as next-generation double perovskite oxides: a comprehensive first principles study on the stability, mechanical properties, electronic properties and thermophysical properties

Abstract Six similar compounds Ba 2 MNO 6 (M = Y, Sc; N = Nb, V, Ta) are obtained by elemental substitution of three double perovskite oxides Ba 2 YNbO 6 , Ba 2 YTaO 6 and Ba 2 ScTaO 6 that have been synthesized experimentally. The stability, mechanical, electronic properties and thermal conductivity of double perovskite oxides Ba 2 MNO 6 (M = Y, Sc; N = Nb, V, Ta) are explored using the ab-initio methods. The negative formation enthalpy and positive phonon frequencies confirm double perovskite oxides Ba 2 MNO 6 have thermodynamic and kinetic stability. Ba 2 MNO 6 (M = Y, Sc; N = Nb, V, Ta) are found to be anisotropic and exhibit brittle behavior. Electronic structure calculations confirm that these double perovskite oxides are direct bandgap semiconductors, with bandgaps of 3.106 eV, 1.554 eV, 3.451 eV, 2.877 eV, 1.444 eV and 3.203 eV, respectively. Electronic effective mass and hole effective mass have small absolute values suggests that the carrier mobility in these compounds may be higher and have a better potential for photovoltaic transformation. Comparing with most semiconductor materials, these double perovskite oxides have a high melting point of approximately 2000 K. The lattice thermal conductivity of all compounds decreases as the temperature increases, which is consistent with the general law of thermal conduction. The minimum thermal conductivity demonstrates that the double perovskite oxides could be superior in electromechanical and thermoelectric applications. Low lattice thermal conductivity facilitates can improve thermoelectric ZT values.