A novel two-dimensional SiO sheet with high-stability, strain tunable electronic structure, and excellent mechanical properties* *Project supported by the National Natural Science Foundation of China (Grant Nos. 12004102 and 11847094), the China Postdoctoral Science Foundation (Grant No. 2020M670836), and the Open Project of State Key Laboratory of Superhard Materials in Jilin University (Grant No. 201703).

Abstract

Using the structure search of particle swarm optimization (PSO) algorithm combined with density functional theory (DFT), we conduct a systematic two-dimensional (2D) material research on the SiO and discover a P2 monolayer structure. The phonon spectrum shows that the 2D P2 is dynamic-stable under ambient pressure. Molecular dynamics simulations show that 2D P2 can still exist stably at a high temperature of 1000 K, indicating that 2D P2 has application potential in high-temperature environments. The intrinsic 2D P2 structure has a quasi-direct band gap of 3.2 eV. The 2D P2 structure can be transformed into a direct band gap semiconductor by appropriate strain, and the band gap can be adjusted to the ideal band gap of 1.2 eV–1.6 eV for photovoltaic materials. These unique properties of the 2D P2 structure make it expected to have potential applications in nanomechanics and nanoelectronics.