KTN及其表面界面中氧空位与掺杂离子的第一性原理研究

项目名称： KTN及其表面界面中氧空位与掺杂离子的第一性原理研究

项目编号： No.11204053

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 申艳青

作者单位： 哈尔滨工业大学

项目金额： 25万元

中文摘要： Y.Saito在Nature 上报道 KNbO3 基压电陶瓷所有性能几乎都可以与PZT媲美，由此掀起无铅压电研究热潮。钽铌酸钾(KTN)是研究最多的 KNbO3 基材料，而且掺杂KTN在电光、电控全息、传感器、移相器、上转换激光等器件应用方面潜力巨大。众所周知点缺陷对器件设计至关重要，且第一性原理预测高效省时。因此本项目拟利用杂化密度泛函进行KTN 点缺陷第一性原理研究。探寻缺陷晶格构型并计算电子结构、光学性质和压电特性。给出氧空位形成能和能级位置，重点研究氧空位团簇。理论解释掺杂离子对KTN 压电性能的调控作用，并研究掺杂离子与氧空位联合作用。探索 KTN 表面界面二维电子气形成过程，给出超薄薄膜界面导电的微观机制。本项目发现的新现象与新效应，将进一步扩展无铅 KTN 的研究领域，因此具有重要科学意义，为KTN无铅压电器件应用提供理论基础，具有重大实用价值。

中文关键词： 无铅压电；杂化密度泛函；掺杂离子；二维电子气；氧空位

英文摘要： In Nature,Y.Saito et al.report that most of the piezoelectric properties of a KNbO3-based lead-free piezoelectric ceramic are comparable to those of the PZT. Therefore there has been a flurry of studies on the topic of lead-free piezoceramics. Potassium tantalate niobate (KTN) is KNbO3-based ferroelectric, which has drawn much attention recently, and doping KTNs have considerable technological applications in electro-optics, electroholography, transducers, microwave tunable phase shifter, upconversion laser, etc. For instance, in Nature Photonics, A.J.Agranat et al. indicate that copper-doped KTN:Li leads to a completely new paradigm for ultraresolved imaging and microscopy. Point defects have traditionally been considered to play an essential role in device design, and first-principles have been particularly helpful and highly efficient in elucidating the issues. In consequence, we intend to present a first-principles study of defects in KTN by means of hybrid density functional. The KTN supercells are optimized to obtain stable geometry structures, and then the electronic structure, optical properties and piezoelectricity are calculated using the optimized structure. We will pay particular attention to formation energy and clustering of oxygen vacancy. The piezoelectric properties of KTN are often controlled b

英文关键词： lead-free piezoelectric；hybrid density functional；doped ions；two dimensional electron gases；oxygen vacancy