研究目的
Investigating the electronic and optical properties of double perovskite oxides Pb2ScMO6 (M = Ta, Sb) using a first principles approach.
研究成果
The double perovskites Pb2ScMO6 (M = Sb, Ta) exhibit direct band gaps and semiconducting behavior with wide band gaps (e.g., 2.712 eV and 3.842 eV for Pb2ScSbO6 using GGA and mBJ, respectively). The O-atom contributes maximally to DOS in the valence band, and the Sc-atom in the conduction band. Optical properties indicate suitability for optoelectronic applications in the visible and ultraviolet regions, but further experimental studies are needed for validation.
研究不足
The study is theoretical and computational, lacking experimental validation. Results could not be compared with previous theoretical or experimental data due to the absence of reported data for these specific double perovskites. The approximations used (GGA and mBJ) may have inherent limitations in accurately predicting electronic properties.
1：Experimental Design and Method Selection:
The study used density functional theory with the full-potential linearized augmented plane wave (FP-LAPW) method. Exchange and correlation potentials were treated using the generalized gradient approximation (GGA) and modified Becke–Johnson (mBJ) potentials. The Wien2k code was employed for computations.
2：Sample Selection and Data Sources:
The samples were theoretical models of double perovskite oxides Pb2ScMO6 (M = Ta, Sb) with cubic crystal structure (space group Fm-3m). Atomic positions and lattice constants were based on previous studies and optimized using Murnaghan's equation of state.
3：List of Experimental Equipment and Materials:
Computational software (Wien2k code) was used; no physical equipment or materials were mentioned.
4：Experimental Procedures and Operational Workflow:
Calculations involved self-consistency cycles with a 20x20x20 k-mesh in the first Brillouin zone, energy cut-off set to -
5：00 Ry, convergence parameter RmtKmax = 7, Gmax = 12 Bohr–1, and energy convergence criterion of 10–5 Ry. DOS, energy bands, and optical properties (dielectric constants, absorption coefficient, reflectivity) were computed. Data Analysis Methods:
Data were analyzed through plots and comparisons of DOS, energy bands, and optical parameters using the GGA and mBJ methods.
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