First-Principles Study of the Electronic and Optical Properties of Sn-BeO Heterostructure

We have explored the electronic and optical properties of the stanene–BeO heterostructure using density functional theory (DFT), including van der Waals interaction using the DFT-D3 correction method of Grimme. The heterostructure exhibits a significant band gap opening, with 93 meV (PBE) and 141 meV (HSE06) values. The impact of spin–orbit coupling (SOC) has also been studied, with PBE + SOC exhibiting a band gap of 55 meV and HSE06 + SOC exhibiting a band gap of 71 meV. Using the DFT-1/2 method, various optical parameters of BeO and Sn monolayer and Sn-BeO heterostructure were studied. The results show a strong red shift in the absorption coefficient, extinction coefficient, and reflectivity, with a prominent absorption peak in the near-UV and visible regions. A significant second harmonic generation peak of 8 × 10⁴ pm V⁻¹ was also obtained. The excellent optical properties of the heterostructure indicate its potential for use in future optoelectronic devices.