Electronic nature, optical and mechanical properties of M2Pt2O7 (M = Sc, Y and La) pyrochlores: A DFT study

Abstract

M2Pt2O7 (M = Sc, Y, and La) pyrochlores, which are crystalline in face centered cubic (FCC) structure, have been investigated by Generalized Gradient Approximation (GGA) and meta-Generalized Gradient Approximation (meta-GGA) based on Density Functional Theory (DFT). The well-optimized structural parameters have been obtained during the relaxation process and the calculated negative formation enthalpies show their thermodynamic stability and structural synthesizability. Also, the electronic nature have been found to be semiconducting with band gaps as Eg = 1.80 eV (GGA) and 2.49 eV (mBJ) for Sc2Pt2O7, Eg = 1.49 eV (GGA) and 2.20 eV (mBJ) for Y2Pt2O7, and E-g = 0.98 eV (GGA) and 1.75 eV (mBJ) for La2Pt2O7. The calculated mechanical properties indicate that the materials are mechanically stable and it has been found that they are ductile and hard materials. The obtained optical parameters show that M2Pt2O7 (M = Sc, Y, and La) pyrochlores may be considered in electronic device applications due having suitable band gaps and large absorption coefficients.