Effect of electric field on migration of defects in oxides: Vacancies and interstitials in bulk MgO
Effect of electric field on migration of defects in oxides: Vacancies and interstitials in bulk MgO
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电场对氧化物中缺陷迁移的影响：块体 MgO 中的空位和填隙
DOI：
10.1103/physrevb.98.064102
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发表时间：
2018
影响因子：
3.7
通讯作者：
El-Sayed A
中科院分区：
文献类型：
--
作者：
El-Sayed A
在电子器件的正常运行过程中，由金属氧化物组成的介质层经常受到外加电场的影响。许多唯象理论表明，电场强烈影响氧化物薄膜中缺陷的性质和迁移率，甚至可以促进新缺陷的产生。虽然金属氧化物中的缺陷已经在实验和理论上得到了广泛的研究，但外加电场对其结构和迁移势垒的影响还不是很清楚，仍然存在猜测。在这里，我们研究了静态、均匀的电场如何影响典型氧化物MgO中正则缺陷--氧空位和间隙离子--的迁移势垒。利用密度泛函理论(DFT)中的极化理论，对三种不同电荷状态下的缺陷迁移路径进行了电场处理。场的作用表现为系统偶极矩沿迁移路径的变化。计算的势垒变化最大的是带电缺陷，而中性缺陷的变化不大。我们表明，通过将初始态和过渡态之间的偶极矩差(我们定义为有效偶极矩)乘以场强，可以得到与DFT计算值非常一致的势垒变化的估计。这些结果将有助于评估唯象模型的适用性，并阐明现场应用在微电子器件退化、电催化、电池和其他应用中的线性和非线性效应。
Dielectric layers composed of metal oxides are routinely subjected to external electric fields during the course of normal operation of electronic devices. Many phenomenological theories suggest that electric fields strongly affect the properties and mobilities of defects in oxide films and can even facilitate the creation of new defects. Although defects in metal oxides have been studied extensively both experimentally and theoretically, the effect of applied electric fields on their structure and migration barriers is not well understood and still remains subject to speculations. Here, we investigate how static, homogeneous electric fields affect migration barriers of canonical defects—oxygen vacancies and interstitial ions—in a prototypical oxide, MgO. Using the modern theory of polarization within density functional theory (DFT), we apply electric fields to defect migration pathways in three different charge states. The effect of the field is characterized by the change of the dipole moment of the system along the migration pathway. The largest changes in the calculated barriers are observed for charged defects, while those for the neutral defects are barely significant. We show that by multiplying the dipole moment difference between the initial and the transition states, which we define as the effective dipole moment, by the field strength, one can obtain an estimate of the barrier change in excellent agreement with the DFT calculated values. These results will help to assess the applicability of phenomenological models and elucidate linear and nonlinear effects of field application in degradation of microelectronic devices, electrocatalysis, batteries, and other applications.
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影响因子：
3.9
作者：
J. Uehara;K. Aramaki
通讯作者：
J. Uehara;K. Aramaki
影响因子：
3.7
作者：
Klyukin, Konstantin;Alexandrov, Vitaly
通讯作者：
Alexandrov, Vitaly
来自四阶多体微扰理论计算的 N2 的多极矩、极化率和超极化率
DOI：
--
发表时间：
1988
期刊：
影响因子：
--
作者：
G. Maroulis;A. Thakkar
通讯作者：
A. Thakkar
预测的 MgO 中的空位团簇结构及其与氦的相互作用
DOI：
--
发表时间：
2000
期刊：
影响因子：
--
作者：
G. Busker;M. Huis;R. Grimes;A. Veen
通讯作者：
A. Veen
从头算研究电荷局域化对氧化镁中氧缺陷形成和迁移能的影响
DOI：
--
发表时间：
2011
期刊：
Proceedings of the Royal Society A
影响因子：
--
作者：
J. Mulroue;D. Duffy
通讯作者：
D. Duffy