Effects of Intrinsic Surface Defects on Morphology and Electronic Structure of a Thin PtSe₂ Film from First-principles

Among transition-metal dichalcogenide families, PtSe₂ is relatively new. In a bulk form, it was confirmed to be a Dirac semimetal, whereas as a monolayer, it was shown to be semiconducting with a small band gap. Recently, a PtSe₂ monolayer was grown on a Pt substrate and revealed interesting layer-selective Rashba splitting. Compared to MoS₂ family, PtSe₂ has a stronger bonding between neighboring monolayers, which allows to observe defects slightly deeper into the surface. Very recently, a scanning tunneling microscopy and spectroscopy (STM/S) study revealed interesting morphology changes depending on types of intrinsic surface defects on a thin PtSe₂ film grown on sapphire. Motivated by this, we investigate morphology, formation energies and electronic structures of five distinct surface defects in a thin PtSe₂ film, by using supercells within density-functional theory. Our results will be compared with the STM/S experimental data.