Abstract
The structural, electronic, optical, thermodynamic and thermoelectric properties of double perovskites Ba(2)MTaO(6) (M = Er, Tm) have been studied. These alloys stabilize in cubic structure with paramagnetic phases and structural parameters that are in good agreement with experimental results. The elastic parameters reveal both materials as being super hard and brittle in nature. The band profile displays the direct bandgap semiconducting behavior of both compounds in the spin-up channels. The optical coefficients, viz. optical conductivity, reflectivity and electron energy loss, are intended for a photon energy of up to 14 eV to perceive the optical response. The effects of temperature and pressure on the thermodynamic properties have also been evaluated via the quasi-harmonic Debye model. Post-DFT treatment was performed to explore the thermoelectric properties; both perovskites exhibit a colossal power factor of 90 × 10(11) W m(-1) K(-2) s(-1) and 5 × 85 × 10(11) W m(-1) K(-2) s(-1) for Ba(2)TmTaO(6) and Ba(2)ErTaO(6), respectively, at 800 K.