Investigating the Structural, Elastic, Pressure-Dependent Electronic and Optical Properties of Antiferromagnetic HoPdBi and HoPtBi Alloys

In this paper, we investigated the structural, elastic, topological-electronic properties as well as optical properties of two half-Heusler (HH) heavy fermions-based compounds: HoPtBi and HoPdBi. We accomplished our calculations in the framework of density functional theory (DFT), based on the full potential linearized augmented plane wave (FP-LAPW). Both compounds are antiferromagnetic (AFM) type-II as reported by experimental data so we carried out our study in the AFM type-II configuration. Considering the spin-orbit coupling, we found that the hydrostatic pressure leads to a phase transition from the trivial semimetal to the topological semimetal (TSM) because of band inversion for HoPdBi with no apparent effect of hydrostatic pressure on the topological phase for HoPtBi. We also studied their optical properties, without and with hydrostatic pressure. The first peak in reflectivity, absorption, optical conductivity spectra and energy loss factor are strongly influenced by the hydrostatic pressure. Both compounds exhibit a considerable first absorption peak in the visible and ultraviolet ranges and they are best candidates for solar cells considered essential in renewable energy.