Npj Comput. Mater.: 周益春教授团队突破HfO2基铁电薄膜辐照位移损伤的分子动力学模拟

海归学者发起的公益学术平台

分享信息，整合资源

交流学术，偶尔风月

近日，西安电子科技大学先进材料与纳米科技学院周益春教授团队在HfO₂铁电薄膜辐照效应领域取得突破。该研究采用深度学习与排斥表相结合的方法，开发了一种适用于HfO₂铁电薄膜的势函数，将密度泛函理论（DFT）的高精度与分子动力学的高效性相结合，为HfO₂铁电薄膜在辐照环境下的位移损伤研究提供了创新性的解决方案。

深度学习与排斥表相结合的深度学习训练方法

这一成果发表在npj Computational Materials 10:270 （2024），题为“A model for studying displacement damage inirradiated HfO2 ferroelectric thin films”。文章的第一通讯单位为西安电子科技大学，材料院研究生张彦军和副教授陈华共同提出了模型的建立方法，通讯作者为周益春教授和陈华副教授。

所建立的模型能够准确预测HfO₂中多种晶相的性能，包括PO相(Pca2₁),T相(P4₂/nmc),AO相(Pbca), 和M相 (P2₁/c),更重要的是可以精确描述辐照过程中原子碰撞分离的动态过程，保证了用于预测辐照位移损伤时的准确性。计算出铪原子、三配位氧原子和四配位氧原子的位移阈值能量，分别为57.72 eV、41.93 eV和32.89eV，这是描述位移损伤的主要特性。

Figure Displacement threshold energy for different incidencedirections of PKAs in HfO₂. (a) Schematic of the unit cellillustrating the different incidence directions of PKAs, (b) Displacementthreshold energy of O₃atoms, (c) Displacement threshold energy of O₄atoms, and (d) Displacement threshold energy ofHf atoms.

不同入射方向 PKAs 在 HfO₂ 中的位移阈能

随着初级碰撞原子（PKAs）能量的增加，氧原子PKAs和铪原子PKAs的缺陷形成概率（DFP）逐渐升高，并在高能量时趋于1。在能量低于80.27 eV时，氧PKAs更容易形成点缺陷；而能量高于此阈值时，铪PKAs的缺陷形成概率更高，因为氧PKAs更倾向于形成替换环，一定程度上，抑制了点缺陷的生成。

不同 PKAs能量下的缺陷形成概率(DFP)和缺陷数

Deep learning potential model of displacement damage in hafnium oxide ferroelectric films

Hua Chen, Yanjun Zhang,Chao Zhou and Yichun Zhou

A model for studying displacement damage in irradiated HfO2 ferroelectric thin films was developed using deep learning and a repulsive table, combining the accuracy of density functional theory with the efficiency of molecular dynamics. This model accurately predicts the properties of various HfO2 phases, such as PO (Pca21), T (P42/nmc), AO (Pbca), and M (P21/c), and describes the atom collision-separation process during irradiation. The displacement threshold energies for the Hf atoms, three-coordinated O atoms, and four-coordinated O atoms are 57.72, 41.93, and 32.89 eV, respectively. The defect formation probabilities (DFPs) for the O primary knock-on atoms (PKAs) and Hf PKAs increase with energy, reaching 1. Below 80.27 eV, the O PKAs are more likely to form point defects than the Hf PKAs. Above this energy, the Hf PKAs have a higher DFP because the O PKAs form replacement loops more easily, inhibiting the generation of point defects. This study provides a comprehensive understanding of defect formation, which is crucial for increasing the reliability of HfO2 ferroelectric devices under irradiation.