First-principles studies on electronic band structure of PdSe₂ with GW approximation

We studied the electronic band structure of PdSe₂ using the density functional theory (DFT) and the GW method. It is known that PdSe₂, a material with stacks of pentagonal layer structure, has a semiconducting band structure experimentally. However, DFT calculations show that bulk PdSe₂ has a semi-metallic band structure because of DFT underestimation of the band gap of the material. To obtain the band gap of PdSe₂ correctly, we calculated the quasiparticle band structure of bulk PdSe₂ using the one-shot GW method and obtained a band gap which is consistent with experimental results. Then we calculated the electronic structure of two-dimensional PdSe₂ to investigate the layer-number dependence on the energy gap. We discuss band-to-band transition energies and other physical properties obtained from band structures of PdSe₂.