Magnetic, optical and electron transport properties of n-type CeO2: Small polarons versus Anderson localization
Magnetic, optical and electron transport properties of n-type CeO2: Small polarons versus Anderson localization
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n 型 CeO2 的磁、光和电子传输特性：小极化子与安德森局域化
DOI：
10.1103/physrevb.95.045203
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发表时间：
2017
影响因子：
3.7
通讯作者：
J. Hwang
中科院分区：
文献类型：
--
作者：
T. Kolodiazhnyi;T. Charoonsuk;Y.-S. Seo;S. Chang;N. Vittayakorn;J. Hwang
我们报告的磁化率，电导率和光吸收的其中= Nb，Ta和。直流电导率遵循一个简单的热激活Arrhenius型行为在-700 K范围内的斜率atK的变化。高温激活能随掺杂浓度的增加而逐渐增大，从~ 220 meV。低温电导率的活化能显示出一个宽的最小值meV在。在Holstein小极化子、安德森局域化和Jahn-Teller畸变模型的框架下分析了电子输运和局域化机制。在声子辅助电子输运中，考虑横向光学声子而不是纵向声子时，对小极化子迁移率的拟合得到了显着改善。这是与氧配体强轨道相互作用的间接证据，类似于的情况。基于实验数据与模型的比较，提出了缺陷诱导的随机电场对施主掺杂氧化铈中的电子局域化的主要贡献。
We report magnetic susceptibility, electrical conductivity and optical absorption ofwhere= Nb,Ta and. The dc conductivity follows a simple thermally activated Arrhenius-type behavior in the–700 K range with a change in slope atK. The high-temperature activation energy shows gradual increase fromto 220 meV as the dopant concentration increases. The activation energy of the low-temperature conductivity shows a broad minimum ofmeV at. Electron transport and localization mechanisms are analyzed in the framework of the Holstein small polaron, Anderson localization, and Jahn-Teller distortion models. The fit to the small polaron mobility is dramatically improved when, instead of the longitudinal phonons, the transverse optical phonons are considered in the phonon-assisted electron transport. This serves as an indirect evidence of a strongorbital interaction with the oxygen ligands, similar to the case of. Based on comparison of the experimental data to the models, it is proposed that the defect-induced random electric fields make the dominant contribution to the electron localization in donor-doped ceria.