Modelling of electronic and structural strain effects in grain boundaries of semiconducting oxides

半导体氧化物晶界中电子和结构应变效应的建模

基本信息

批准号：
317610723
负责人：
Professor Dr. Karsten Albe
金额：
--
依托单位：
Fachgebiet Materialmodellierung
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/317610723?language=en
关键词：
Modelling electronic structural strain effects

项目摘要

The influence of mechanical stress conditions on the electronic conductivity of doped and undoped grain boundaries in piezoelectric oxides is investigated by means of electronic structure calculations based on density functional theory (DFT) and atomistic modelling. The calculations aim for modelling the chemical and structural reconstruction of grain boundaries (GB) of different orientations as function of mechanical strain, temperature and oxygen partial pressure. The goal is to simulate the influence of external strain on the electronic density of states within the GB. Here, it is of special interest, how mechanical and electrical fields couple to the distribution of dopants, open volume and the electronic structure of grain boundaries. Detailed examinations of bicrystal-arrangements for grain boundaries of different orientation (tilt and twist boundaries) upon uniaxial and multi-axial mechanical load are planned. Additionally, the influence of heat treatment under mechanical load on grain boundary properties as well as the characteristic time scales for structural rearrangement processes will be estimated by means of calculated activation barriers for diffusive transport of intrinsic and extrinsic defects in the area of mechanically loaded grain boundaries. In order to model the influence of microstructural parameters on the observed effects, molecular statics and molecular dynamics simulations base on classical interatomic potentials are planned. In perspective, the simulations aim to identify and to quantify those physical parameters, which are necessary to model the characteristics of mechanically tunable components

基于密度功能理论（DFT）和原子建模的电子结构计算，研究了机械应力条件对压电氧化物中掺杂和未掺杂晶界电子电导率的影响。该计算旨在建模不同方向的晶界（GB）的化学和结构重建，作为机械应变，温度和氧部分压力的功能。目的是模拟外部应变对GB内状态的电子密度的影响。在这里，这是特别感兴趣的，机械和电场如何与掺杂剂的分布，开放体积和晶界的电子结构相结合。计划在单轴和多轴机械载荷上对不同方向（倾斜和扭曲边界）的晶界进行双晶式排序。此外，机械负荷下的热处理对晶界特性的影响以及结构重排过程的特征时间尺度将通过计算的激活屏障来估计，以在机械载荷晶界区域扩散内在和外部缺陷的扩散。为了模拟微观结构参数对观察到的效果的影响，计划了基础分子静态和分子动力学模拟对经典原子间电位的影响。从角度来看，模拟旨在识别和量化这些物理参数，这是建模机械可调组件的特征所必需的