单层
压电
材料科学
铁电性
凝聚态物理
金属
纳米技术
光电子学
物理
复合材料
电介质
冶金
作者
Mohammad Noor‐A‐Alam,Michael Nolan
出处
期刊:Nanoscale
[The Royal Society of Chemistry]
日期:2022-01-01
卷期号:14 (32): 11676-11683
被引量:6
摘要
Flexible two-dimensional (2D) piezoelectric materials are promising for applications in wearable electromechanical nano-devices such as sensors, energy harvesters, and actuators. A large piezo-response is required for any practical applications. Based on first-principles calculations, we report that ferroelectric TiOX2 and multiferroelectric VOX2 (X = F, Cl, and Br) monolayers exhibit large in-plane stress (e11) and strain (d11) piezoelectric coefficients. For example, the in-plane piezo-response of TiOBr2 (both e11 = 28.793 × 10-10 C m-1 and d11 = 37.758 pm V-1) is about an order of magnitude larger than that of the widely studied 1H-MoS2 monolayer, and also quite comparable to the giant piezoelectricity of group-IV monochalcogenide monolayers, e.g., SnS. Moreover, the d11 of MOX2 monolayers - ranging from 29.028 pm V-1 to 37.758 pm V-1 - are significantly higher than the d11 or d33 of commonly used 3D piezoelectrics such as w-AlN (d33 = 5.1 pm V-1) and α-quartz (d11 = 2.3 pm V-1). Such a large d11 of MOX2 monolayers originates from low in-plane elastic constants with large e11 due to large Born effective charges (Zij) and atomic sensitivity to an applied strain. Moreover, we show the possibility of opening a new way of controlling piezoelectricity by applying a magnetic field.
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