摘要
近期在范德华材料中发现的滑移铁电性因其具备在原子厚度上实现微型功能器件的潜力而引起了广泛的兴趣.然而,由于元件层间的范德华耦合相对较弱,导致固有的电极化强度较低,在很大程度上制约了该性质的实际应用.我们以多层六方氮化硼(h-BN)为例,采用从头算方法,发现施加垂直压力可以显著增强滑移铁电性.在4.63 GPa的中等压力下,双层和三层h-BN的极化强度分别提高了125.58%和104.79%.此外,当弯曲多层h-BN材料时,铁电可以与挠曲电进一步耦合,从而产生更大的电极化.值得注意的是,这一具有的压力增强电极化效应的铁电性可以在无需外加电场的情况下调节弯曲双层h-BN的带隙.这些结果凸显了滑移铁电性可作为一种新的自由度来调控范德华材料中的力电耦合.
The recent discovery of sliding ferroelectricity in van der Waals(vdw)materials has attracted tremendous interest owing to its potential for miniaturizing functional devices with atomic thicknesses.However,the practical applications of this intriguing property are largely hindered by its inherently small electric polarization resulting from weak vdW coupling between the component layers.Using boron nitride(BN)multilayers as a prototype,our ab initio calculations demonstrate that vertical pressure can substantially enhance sliding ferroelectricity.Specifically,a moderate pressure of 4.63 GPa can increase the electric polarization by 125.58%in bilayers and 104.79%in trilayers.Furthermore,when the multilayers are bent,the ferroelectricity can be further coupled with flexoelectricity to yield an amplified net polarization.Notably,the pressure-enhanced electric polarization of ferroelectricity can narrow the band gap of bent BN multilayers without requiring an external electric field.These findings present sliding ferroelectricity as a novel degree of freedom formanipulating electromechanical coupling invdWmaterials.
作者
郭瀚泽
轩啸宇
张助华
GUO HanZe;XUAN XiaoYu;ZHANG ZhuHua(State Key Laboratory of Mechanics and Control for Aerospace Structures,Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education,Institute for Frontier Science,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)
出处
《中国科学:物理学、力学、天文学》
CSCD
北大核心
2024年第5期170-179,共10页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家自然科学基金(编号:12261160367,12225205,22073048,T2293691)
江苏省高等学校重点学科建设项目资助。
关键词
滑移铁电
垂直压力
多层六方氮化硼
力电耦合
sliding ferroelectricity
vertical pressure
hexagon boron nitride multilayers
mechanical-electrical coupling