Electron structure of bulk and two-dimensional SrTiO₃ (2D-SrTiO₃) were calculated using the first-principle approach based on the density functional theory (DFT) with GGA + U methods. An accurate direct band gap of bulk SrTiO₃ of 3.52 eV and indirect band gap of 3.06 eV were obtained with the optimum U_Ti-3d = 6.0 eV and U_Sr-3d = 3.0 eV. It is found that the electronic structure of 2D-SrTiO₃ is strongly affected by the surface atoms. Most interestingly, the band gap of 2D-SrTiO₃ is much smaller than that of the bulk material and is nearly independent of thickness. The origin of this behavior is traced to the nature of the conduction band in 2D-SrTiO_3.

基于第一性原理，基于密度泛函理论（DFT），采用GGA + U方法，计算了本体和二维SrTiO ₃（2D-SrTiO ₃）的 电子结构。在最佳的U _Ti-3d  = 6.0 eV和U _Sr-3d  = 3.0 eV的条件下，可获得准确的3.52 eV的本体SrTiO ₃直接带隙和3.06 eV的间接带隙。发现2D-SrTiO ₃的电子结构受到表面原子的强烈影响。最有趣的是2D-SrTiO ₃的带隙它比散装材料小得多，并且几乎与厚度无关。此行为的起源可追溯到2D-SrTiO _3中导带的性质_。