▎ 摘　　要

The present study investigated the electronic and optical properties of the graphene-like Be3C2 monolayer based on the density-functional theory (DFT) calculations. Dirac materials (DMs) due to their linear dispersion and ultra-high Fermi velocity show a variety of intriguing properties, but their novel physical properties are still open issues. Be3C2 monolayer exhibits a Dirac feature with a hexagonal honeycomb structure which previously has been predicted as a stable graphene-like 2D material. Be3C2 monolayer shows a zero-gap semiconducting behavior that the Dirac state around the Fermi level is composed of hybridized P orbitals of the C and Be atoms. Most interesting, the dielectric function shows semiconducting character with an optical gap around 1.6 eV in the case of out-of-plane polarization. Moreover, plasmons are observed along the in-plane polarization and infrared (IR) region which is associated with the highest peak in the energy loss function. Also, a significant drop in the conductivity curve is observed at the edge of the visible range. The first absorption peaks along the in-plane polarization appears in IR region and at 0.7 eV, corresponding the first peak in the conduction curve and also the highest absorption peak for both directions occurs around 7.5 eV. These results illustrate the similarities between graphene and Be3C2 monolayer, which promise high potential of the Be3C2 monolayer in a broad variety application in optoelectronics devices.