1T'-RuO2 monolayer: First-principles study of excitonic, optoelectronic, vibrational, and thermodynamic properties

The monoclinic 1T'-RuO2 monolayer have been studied using density functional theory (DFT) considering the norm-conserved pseudopotentials within the generalized gradient approximation (GGA) and the hybrid functional HSE06. A direct bandgap E-g = 0.35 eV (E-g = 1.11 eV) was obtained within the GGA-PBE (HSE06) level of calculation, while a combination of a Tight binding plus BSE (TB+BSE) approach was applied for the investigation of optical and excitonic properties. 1T'-RuO2 exhibits significant absorption in the ultraviolet and visible regions and also shows a strong optical linear dichroism. The solution of Bethe-Salpeter equation showed relevant excitonic effects in this system, with an exciton binding energy of 0.69 eV. In addition, the infrared and Raman spectra were obtained and assigned, as well as, the phonon dispersion relation. Finally, from the thermodynamics potentials calculations within the PBE functional, the free Gibbs energy indicates that this monolayer could be potentially synthesized spontaneously at low temperatures.

Automated summary

The monoclinic 1T'-RuO2 monolayer was investigated using density functional theory. The calculations considered norm-conserved pseudopotentials within the generalized gradient approximation and the hybrid functional HSE06. The study revealed significant absorption in the ultraviolet and visible regions, strong optical linear dichroism, and relevant excitonic effects with an exciton binding energy of 0.69 eV.