سنة النشر

2025

العنوان

Structural, Relaxation, and Electronic Properties of the Bulk and (1 1 1) Surfaces of Cubic Perovskite RbTaO3: A First-Principles Study

الخلاصة

We examined the structural, relaxation, and electronic properties of the bulk and (1 1 1) surfaces of cubic perovskite RbTaO3 using first-principles density functional theory (DFT). We used the DFT-VASP code for our calculations. The Rb and O atoms in the RbO3 (1 1 1) termination had a large atomic displacement (ΔZ) in the top and ninth layers, whereas the Ta atoms in the termination had a large ΔZ in the second and eighth layers. The Rb and O atoms in the Ta (1 1 1) termination had a large ΔZ in the second and eighth layers. The surface energy (Esurf) calculated for the RbO3 (1 1 1) termination was 7.96 eV, smaller than that for the Ta (1 1 1) termination, with Esurf of 7.11 eV. The cleavage energy required at the Ta or RbO3 (1 1 1) termination was 8.77 eV. The bulk system exhibited a semiconducting nature with a bandgap (Eg) of 2.25 eV. The RbO3 and Ta terminations exhibited half-metallic ferromagnetism (HMF) with a spin magnetic moment of 5.00 μβ. The Eg values of the RbO3 and Ta (1 1 1) surfaces were 2.45 eV and 2.55 eV, respectively. We also used the DFT-B3LYP CASTEP code to calculate Eg. The Eg of the RbTaO3 bulk was 2.40 eV. The Eg values of the RbTaO3 (1 1 1) surface were 2.65 and 2.50 eV for the Ta and RbO3 terminations, respectively. We also calculated the atomic populations (Q) and variations (ΔQ) of the Ta and RbO3 (1 1 1) terminations and compared them with those of the bulk system. © The Minerals, Metals & Materials Society 2024.