取向相关的Pb(Zr_(0.52)Ti_(0.48))O_(3 )外延薄膜的相图和介电性能  

Phase diagram and dielectric properties of orientationdependent Pb(Zr_(0.52)Ti_(0.48))O_(3 ) epitaxial films

作　　者：白刚 林翠[1] 刘端生 许杰 李卫 高存法 Bai Gang;Lin Cui;Liu Duan-Sheng;Xu Jie;Li Wei;Gao Cun-Fa(College of Electronic and Optical Engineering&College of Microelectronics,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;Laboratory of Solid State Microstructures,Nanjing University,Nanjing 210093,China;State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京邮电大学电子与光学工程学院、微电子学院,南京210023 [2]南京大学固体微结构物理国家重点实验室,南京210093 [3]南京航空航天大学机械结构力学控制国家重点实验室,南京210016

出　　处：《物理学报》2021年第12期288-298,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51602159,61804080)资助的课题。

摘　　要：探索相变和构建相图对于铁电物理和材料研究至关重要,是相关理论和实验领域的研究焦点.随着计算机和人工智能的迅猛发展,利用机器学习方法并结合其他计算方法如第一性原理,可以从海量的材料数据中选择符合目标的材料种类,从而大大节约了实验成本.本文利用神经网络方法和唯象理论计算准确预测出不同取向铁电薄膜的相图中可能出现的相,进而建立了(001),(110)和(111)取向Pb(Zr_(0.52)Ti_(0.48))O_(3 )铁电薄膜的温度-应变相图,并计算了室温下不同取向的极化和介电性能.通过预测准确率及损失随迭代次数的变化,发现深度神经网络方法在薄膜温度-应变相图构建及预测相的种类方面具有准确快速等优势.通过对室温极化与介电性能进行分析,发现(111)取向的Pb(Zr_(0.52)Ti_(0.48))O_(3 )薄膜面外极化最大,面外介电系数最小,且二者对应变变化都不敏感.这对设计需要介电系数和极化性能处于稳定工作环境及对运行有特殊要求的微纳器件具有十分重要的理论指导意义.Exploring phase transition behaviors and constructing phase diagrams are of importance for theoretically and experimentally studying ferroelectric physics and materials.Because of the rapid development of computers and artificial intelligence,especially machine learning methods combined with other computational methods such as first principle calculation,it is possible to predict and choose appropriate materials that meet the target requirements from a large number of material data,which greatly saves the cost of experiments.In this work,we use neural network method and phenomenological theoretical calculations to accurately predict the phase structures that may appear in the phase diagrams of different orientated Pb(Zr_(0.52)Ti_(0.48))O_(3 )ferroelectric films,and establish the temperature-strain phase diagrams of(001),(110)and(111)oriented thin film,and calculate the polarization and dielectric properties of different oriented films at room temperature.By analyzing the changes of prediction accuracy and loss with the number of iterations,it is found that the deep neural network method has the advantages of high accuracy and speed in the construction of the film temperature-strain phase diagram and the prediction of the types of phases.Through the analysis of the room temperature polarization and dielectric properties,it is found that the(111)-oriented Pb(Zr_(0.52)Ti_(0.48))O_(3 ) film has the largest out-of-plane polarization and the smallest out-of-plane dielectric coefficient,and they are insensitive to misfit strain.This work provides guidelines for designing micro-nano devices that require the stable dielectric coefficient and polarization performance in the special working environment and operation.

关 键 词：铁电薄膜 相图 机器学习 唯象理论 

分 类 号：TB383.2[一般工业技术—材料科学与工程]