论文标题
单层中的固有压电$ \ mathrm {xsi_2n_4} $（x = ti，Zr，Zr，hf，cr，mo和w）
Intrinsic piezoelectricity in monolayer $\mathrm{XSi_2N_4}$ (X=Ti, Zr, Hf, Cr, Mo and W)
论文作者
论文摘要
通过实验合成的$ \ MATHRM {MOSI_2N_4} $（\ TextColor [RGB] {0.00,0.00,00,1.00} {Science 369，670-674（2020}） Zr，HF，CR，MO和W）通过密度功能理论（DFT）研究。在六个单层中，$ \ mathrm {crsi_2n_4} $具有最佳的压电应变系数$ d_ {11} $ 1.24 pm/v，第二个为1.15 pm/v，for $ \ mathrm {mosi_2n_4} $。以$ \ mathrm {mosi_2n_4} $为例，将应变工程应用于改善$ d_ {11} $。发现拉伸双轴菌株可以增强$ \ mathrm {mosi_2n_4} $的$ d_ {11} $，而在4 \％的$ d_ {11} $相对于未经培养的人，$ d_ {11} $可以提高107 \％。通过p或按$ \ mathrm {mosi_2n_4} $替换n，$ d_ {11} $可以大大提高。对于$ \ mathrm {mosi_2p_4} $和$ \ mathrm {mosi_2as_4} $，$ d_ {11} $高达4.93 pm/v和6.23 pm/v和6.23 pm/v，这主要是由于较小的$ c_ {11}} -c_ {11} -c_ {12} - co {12 e {12 e {podition podifition cogtion foriew cogution cogution cogution foriews coditive to pie forie $ e_ {11} $相对于$ \ mathrm {mosi_2n_4} $。在单层$ \ mathrm {XSI_2N_4} $中发现了这种压电性，可以为纳米级设备实现主动感测，致动和新的电子组件，并建议进行实验探索。
Motived by experimentally synthesized $\mathrm{MoSi_2N_4}$ (\textcolor[rgb]{0.00,0.00,1.00}{Science 369, 670-674 (2020})), the intrinsic piezoelectricity in monolayer $\mathrm{XSi_2N_4}$ (X=Ti, Zr, Hf, Cr, Mo and W) are studied by density functional theory (DFT). Among the six monolayers, the $\mathrm{CrSi_2N_4}$ has the best piezoelectric strain coefficient $d_{11}$ of 1.24 pm/V, and the second is 1.15 pm/V for $\mathrm{MoSi_2N_4}$. Taking $\mathrm{MoSi_2N_4}$ as a example, strain engineering is applied to improve $d_{11}$. It is found that tensile biaxial strain can enhance $d_{11}$ of $\mathrm{MoSi_2N_4}$, and the $d_{11}$ at 4\% can improve by 107\% with respect to unstrained one. By replacing the N by P or As in $\mathrm{MoSi_2N_4}$, the $d_{11}$ can be raise substantially. For $\mathrm{MoSi_2P_4}$ and $\mathrm{MoSi_2As_4}$, the $d_{11}$ is as high as 4.93 pm/V and 6.23 pm/V, which is mainly due to smaller $C_{11}-C_{12}$ and very small minus or positive ionic contribution to piezoelectric stress coefficient $e_{11}$ with respect to $\mathrm{MoSi_2N_4}$. The discovery of this piezoelectricity in monolayer $\mathrm{XSi_2N_4}$ enables active sensing, actuating and new electronic components for nanoscale devices, and is recommended for experimental exploration.
