Electronic and optical properties of PbFCl and PbFI monolayers using density functional theory and beyond

In the two years, the TMDs materials perform a hugely great role in that they represent other resources of getting a material with bandgap energy and stable dynamically for electronics purposes. Many subjects have confirmed that TMDs mono or bi-layer could offer properties superior to those of graphene. Astonishingly, few of them have synthesized. Based on the density functional theory and beyond, we study the electronic, vibrational, and optical properties of new 2D materials, i.e., the alkaline-earth fluoro-halides monolayers such as PbFCl and PbFI. By computing the phonon spectra of PbFCl and PbFI monolayers, we have shown that they are dynamically stable. We obtained the bandgaps of these monolayers as achieved with the GW approximation are 6.38 and 6.64 eV. Also, we found that the strength of the electric field decreases the bandgap energy of our compounds and modifies the location of CBM and VBM. Further, we obtained by employing the picture marks seen in the calculated STM images and their accompanying geometries as creating slabs it is probable to build these 2D monolayers.