Optoelectronic, Magnetic, Electric Field Gradient, NMR, and Thermoelectric Properties of RCoO3 (R = Nd, Sm, Dy) Compounds Using GGA plus Hubbard Approach for Energy Harvesting

This study investigates the optoelectronic, magnetic, thermoelectric, hyperfine field (HFF), electric field gradient (EFG), and nuclear magnetic resonance (NMR) properties of rare-earth cobaltite compounds RCoO 3 (R = Nd, Sm, and Dy) using first-principles calculations within the framework of density functional theory (DFT) with the GGA+U method. The calculated band structures reveal direct band gaps, indicating semiconducting behavior for all three compounds, although DyCoO 3 and SmCoO 3 display insulating characteristics in the spin-up channel. Optoelectronic analysis shows that these compounds exhibit weak absorption in the visible range and pronounced absorption in the ultraviolet region, suggesting their potential for UV-filtering applications. From a magnetic standpoint, DyCoO 3 presents the largest atomic moments, accompanied by strong hyperfine and dipolar interactions, whereas NdCoO 3 , despite a relatively weaker hyperfine field, demonstrates a significant orbital contribution from the Co atom. These differences primarily arise from the unique electronic structures of the rare-earth atoms and their hybridization with cobalt within the lattice. Additionally, the study highlights that NMR parameters are highly sensitive to the spin state, with the lanthanide atoms playing a pivotal role in determining the magnetic behavior. The thermoelectric performance of RCoO 3 (R = Nd, Sm, Dy) is shown to depend critically on the interplay between electrical and thermal transport. Overall, these findings underscore how the properties of cobaltite perovskites can be tailored through rare-earth substitution, making them promising candidates for applications in optoelectronic, magnetic, and thermoelectric devices.