Functionalization of two-dimensional PbTiO3 film by surface modification: a first-principles study
Functionalization of two-dimensional PbTiO3 film by surface modification: a first-principles study
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DOI：
10.1016/j.apsusc.2021.150268
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发表时间：
2021-06
影响因子：
6.7
通讯作者：
Yuanbin Xue;Yao Guo;Cuihuan Geng
中科院分区：
文献类型：
--
作者：
Yuanbin Xue;Yao Guo;Cuihuan Geng
超薄铁电薄膜中的自发极化通常受到退极化场的严重抑制，阻碍了其实际应用。本文利用第一线原理计算，探索了一种在二维（2D） pbtio3薄膜中引入自发极化的方法，分析了其潜在的机制，并讨论了其可能的应用。我们的研究结果表明，通过适当的表面修饰可以获得强自发极化，金属丰度和磁性。极化是由层掺杂引起的电场引起的，并且可以通过改变极化来连续调谐带隙。特别是，在双层掺杂体系中，价带最大值（VBM）和导带最小值（CBM）的电子态分别倾向于分布在p掺杂和n掺杂表面，这可能有助于电子-空穴对的分离。我们的发现应该有助于实现具有各种功能的二维钙钛矿基材料，并提高对其性质的理解。
Spontaneous polarization in ultrathin ferroelectric films is usually severely suppressed by a depolarization field, which hinders practical applications. Here, using first-principle calculations, we explored a way of introducing spontaneous polarization in two-dimensional (2D) PbTiO3films, analyzed the underlying mechanisms, and then discussed its possible applications. Our results demonstrate that strong spontaneous polarization, metallicity, and magnetism can be achieved by making appropriate surface modifications. Polarization arises from an electric field that is caused by layer-doping, and the bandgap can be continuously tuned by varying the polarization. In particular, in double layer-doped systems, electronic states at the valence band maximum (VBM) and conduction band minimum (CBM) tend to be distributed on thep-doped andn-doped surfaces, respectively, and this may contribute to the separation of electron-hole pairs. Our findings should be beneficial to achieve 2D perovskite-based materials that have various functionalities and improve the understanding of their properties.