Tunable structure and electronic properties of multilayer PtSe2

Two dimensional (2D) materials such as graphene and transition metal dichalcogenide (TMDC) like MoS2, WTe2 have brought widespread attention as their novel 2D confined properties and applications in nano devices. Among them, the up to date multilayer PtSe2 has been reported to be high mobility, air stable and possess novel phenomenon like Dirac fermions but to date have little study as the tunable electronic properties via structural control. Here we use the first principle calculations based on density functional theory (DFT) to study the tunable structure and electronic properties of monolayer and multilayer PtSe2 by the method of strain. We find that when apply compress strain on monolayer PtSe2 at -3% or more, the photoluminescence will enhance due to a larger density of states at conductance band minimum (CBM). With the increase of layer number, the band gap become small rapidly. The band gap change from 1.3 eV for monolayer to 0.4 eV for bilayer. With three layers, the band gap becomes 0.1 eV. Begin at four layer, the PtSe2 multilayer become a negative band gap semimetal. The DOS under VBM is small for multilayers due to the large splitting between the first valence band with the second valence band. This indicate the possible low photoluminescence strength for these multilayers. Our results can pave a way for the experiment electronic and optical properties tuning in multilayer PtSe2 and possible in the similar TMDCs.