Stability, electronic, optical and thermoelectric properties of site-substituted [formula omitted

Abstract

To unravel the structural and chemical stability, electronic, transport, and optical properties of pristine and site substituted lanthanum vanadate, LaVO3, we employed the density functional theory (DFT) and the dynamical mean field theory (DMFT). The generalized gradient approximation (GGA) and the DMFT with continuous time quantum Monte Carlo (CT-QMC) approach is used for the impurity solver. The variation of the spectral density are studied with different values of the onsite Coulomb interaction (U) and exchange interaction (J), as well as the thermodynamic parameter (β), to investigate the metal insulator transition (MIT) for these materials, which are useful for designing Mottronics, neuromorphic computing devices. The predicted values of U and β for the Mott–Hubbard MIT in La0.40Ca0.60V O3 are consistent with current experimental data. The studied sample’s a characteristic sharp quasi-particle peak is found to be at U = 5 eV and β = 6 (eV)−1. The Mott quantum critical point (QCP) is also computed for an elevated temperatures and it is found at U = 2.95 eV and β = 23.58 (eV)−1. With U = 5.0 eV, β = 10.0 (eV)−1, the clear Mott gaps for La0.40Ca0.60V O3 and La0.60Ca0.40V O3 are estimated as 0.74 eV and 1.64 eV, respectively. The electrical and thermal conductivities are calculated at room temperature using the BoltzTraP code, and they are found to be 2.11 (Ωms)−1 and 1.51 W/(mKs), respectively, for a given chemical potential μ = −0.14 eV of the system. The figure of merit (ZT) is estimated to be 1.78 at μ = −1.44 eV. Larger values of the Seebeck coefficient (S), ZT, and thermoelectric power factor (TPF) indicate that La0.40Ca0.60V O3 system is a good candidate of thermoelectric material. The calculated frequency dependent optical conductivity (Drude weight) on the dependency of U and β for the metal insulator transition supports the other calculations.