Wang Zijian, Liu Zhirong
College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Beijing National Laboratory for Molecular Sciences (BNLMS), Peking University, Beijing 100871, China.
J Phys Chem Lett. 2023 Aug 24;14(33):7549-7555. doi: 10.1021/acs.jpclett.3c01796. Epub 2023 Aug 17.
Normally, the good conductivity of metals and semimetals is incompatible with the piezoelectricity since the internal electric current will dismiss any polarization. However, here, we reveal that the out-of-plane piezoelectric effect can exist in two-dimensional (2D) metallic/semimetallic materials due to their giant anisotropy. A method is developed to calculate the out-of-plane polarization in 2D systems, where the modern theory of polarization based on a Berry-phase approach is not applicable. Detailed calculation and analysis on a Dirac material, the FeB monolayer, show that it has an out-of-plane polarization of 8.3 pC/m and the piezoelectric coefficient of = -59.3 pC/m and = -0.25 pm/V. This work provides a formalism to discover more piezoelectric materials within the vast 2D metallic/semimetallic materials.
通常情况下，金属和半金属的良好导电性与压电性不相容，因为内部电流会消除任何极化。然而，在此我们揭示，由于二维（2D）金属/半金属材料具有巨大的各向异性，面外压电效应能够存在于其中。我们开发了一种方法来计算二维系统中的面外极化，而基于贝里相位方法的现代极化理论在该系统中并不适用。对狄拉克材料FeB单层进行的详细计算和分析表明，它具有8.3 pC/m的面外极化，压电系数为 = -59.3 pC/m以及 = -0.25 pm/V。这项工作提供了一种形式体系，以便在大量的二维金属/半金属材料中发现更多的压电材料。
