单独一对
铁电性
钙钛矿(结构)
卤化物
单层
材料科学
电子
凝聚态物理
电介质
结晶学
化学
无机化学
光电子学
纳米技术
物理
分子
有机化学
量子力学
作者
Junting Zhang,Yu Xie,Jun He,Ke Ji,Xiaofan Shen
出处
期刊:Physical review
[American Physical Society]
日期:2024-07-16
卷期号:110 (3)
被引量:3
标识
DOI:10.1103/physrevb.110.035419
摘要
Two-dimensional (2D) ferroelectricity has attracted considerable interest since its demonstration in van der Waals monolayers. Research on 2D ferroelectricity has so far focused on van der Waals materials, and whether some of the intrinsic ferroelectric mechanisms found in perovskite bulks can be retained to the monolayer limit remains an issue to be solved. Here, we demonstrate that intrinsic ferroelectricity caused by the lone pair electron effect can exist in the inorganic halide perovskite monolayers. This ferroelectricity occurs in halide perovskite monolayers with smaller anions, involving ${\mathrm{Cs}}_{2}{\mathrm{GeF}}_{4}, {\mathrm{Cs}}_{2}{\mathrm{SnF}}_{4}$, and ${\mathrm{Cs}}_{2}{\mathrm{SnCl}}_{4}$. The first two are direct band-gap semiconductors while the latter is an indirect band-gap semiconductor. The octahedral tilt mode also appears in the ground-state structures of these 2D ferroelectrics. The ferroelectric monolayers containing ${\mathrm{F}}^{\ensuremath{-}}$ ions have relatively greater ferroelectric polarization, but also have a higher-energy barrier for ferroelectric switching. This work helps to design 2D ferroelectricity beyond van der Waals materials.
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