The recent success in fabrication of free-standing perovskite oxide films, the thickness of which can be controlled at the atomic scale, breaks new ground in pursuing advanced low-dimensional materials. In this work, the structural characteristics and property modification of 2D (001) SrTiO₃ nanosheets were investigated theoretically. Our results unveil that the system is subject to significant differentiation of Ti–O bonds and several competing structural phases; the properties are layer-dependent, and functionalities are more likely to emerge near the surface; the bandgap can be effectively adjusted by strain, but the in-plane strain has the opposite effect to the out-of-plane strain; electron-doping by V brings about magnetism without breaking the semiconductor nature while hole-doping by Al makes the system exhibit metallic and complex magnetic features. Our findings could partly explain the experimentally observed unusual flexibility and may be also useful to facilitate the understanding of 2D perovskite-based materials.

自立式钙钛矿氧化物薄膜的制造最近取得了成功，其厚度可以在原子尺度上控制，这为追求先进的低尺寸材料开辟了新的领域。在这项工作中，2D（001）SrTiO ₃的结构特征和性能改性理论上研究了纳米片。我们的结果表明，该系统受到Ti-O键和几个竞争结构相的显着差异的影响。这些特性取决于层，并且功能性更可能出现在表面附近。可以通过应变有效地调节带隙，但是面内应变与面外应变的作用相反。V掺杂电子会产生磁性，而不会破坏半导体的性质，而Al掺杂空穴会使系统表现出金属和复杂的磁性。我们的发现可能部分解释了实验观察到的异常灵活性，也可能有助于促进对2D钙钛矿基材料的理解。