Zhang Jun-Jie, Zhu Dongyang, Yakobson Boris I
Department of Materials Science and NanoEngineeringand ⊥Department of Chemistry, Rice University, Houston, Texas 77005, United States.
Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States.
Nano Lett. 2021 Jan 13;21(1):785-790. doi: 10.1021/acs.nanolett.0c04531. Epub 2020 Dec 23.
The realization of multifunctional nanomaterials is both fundamentally intriguing and practically appealing to be used in nanoscale devices. Here, a heterobilayer consisting of realistic 2D-material components of matching lattice symmetry, that is, one being the phase antimonene β-Sb known for its strong spin-orbit coupling and ferroelectric InSe monolayer, is designed and explored with first-principles density functional theory. The ferroelectric polarization of the InSe layer induces distinctly different electronic properties in the bilayer. With polarization directed "inward", the bilayer is a trivial insulator with spatially-indirect band gap (potentially beneficial for photovoltaics). Surprisingly, when polarized "outward", the bilayer displays nontrivial topological state, = 1. This suggests that the external electric field can reversibly switch between these two states, inviting potential applications in future multifunctional devices.
多功能纳米材料的实现，从根本上来说很有趣，并且在纳米级器件中的应用也颇具吸引力。在此，我们设计并运用第一性原理密度泛函理论研究了一种异质双层结构，其由具有匹配晶格对称性的实际二维材料组分构成，即一种是因其强自旋轨道耦合而闻名的相锑烯β-Sb，另一种是铁电InSe单层。InSe层的铁电极化在双层结构中诱导出明显不同的电子性质。当极化方向“向内”时，双层结构是具有空间间接带隙的平凡绝缘体（可能对光伏有益）。令人惊讶的是，当极化方向“向外”时，双层结构呈现非平凡拓扑态， = 1。这表明外部电场可以在这两种状态之间可逆切换，有望在未来的多功能器件中得到应用。
