Two-dimensional nanoporous metal chalcogenophosphates MP2X6 with high electron mobilities

Appling density functional theory, we have theoretically predicted the electronic and structural properties of a series of novel nanoporous two-dimensional (2D) metal chalcogenophosphates of SnP2S6, SnP2Se6, SnP2Te6, GeP2S6, GeP2Se6, GeP2Te6, PbP2S6, which show high electron mobilities. Through systematically analyzing their cleavage energies and phonon spectra, it is found that MP2X6 monolayers are stable and easily exfoliated from their bulks. In terms of electronic structures, the band gaps of monolayer MP2X6 vary from 0.24 eV for GeP2Te6 to 2.4 eV for SnP2S6. Among them, GeP2X6 and PbP2S6 are direct bandgap semiconductors. Significantly, the monolayer MP2X6 possesses higher electron mobility than that of other currently popular two-dimensional materials, such as MoS2, BN, BC2N and hydrogenated graphene, indicating that monolayer MP2X6 could be applied in fast speed nano-electronic devices fields. To further provide the references for experiments and practical devices applications, the band alignments and the strain engineering effects are also examined.