Oxide-ion conduction via interstitials in scheelite-type LaNbO4: a first-principles study
Oxide-ion conduction via interstitials in scheelite-type LaNbO4: a first-principles study
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白钨矿型 LaNbO4 中通过间隙的氧离子传导：第一性原理研究
DOI：
10.1039/c8ta02859a
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发表时间：
2018
影响因子：
--
通讯作者：
K. Matsunaga
中科院分区：
文献类型：
--
作者：
K. Toyoura;Yusuke Sakakibara;T. Yokoi;A. Nakamura;K. Matsunaga
本文以四斜晶系白钨矿结构氧化物为模型体系，采用第一性原理计算方法，对氧化物-间隙离子导电进行了理论分析。在晶体中，通过详尽的结构优化确定了两个氧离子的间隙位点，其位于两个NbO 4四元单元之间以形成Nb 2 O 9单元。在四个基本路径中发现的轻推弹性带方法，三个共同的路径，使间隙氧化物离子迁移在一个很长的范围内都在ab-平面和沿着c-轴，导致几乎各向同性的氧化物离子电导率。然而，氧化物离子电导率估计的基础上的动力学蒙特卡罗方法远远高于报道的实验值。表观活化能也不同，在估计的电导率中为0.4 eV，而在实验电导率中为0.9 eV。由于掺杂剂的捕获效果的额外评估，间隙氧化物离子被发现被强烈捕获的W掺杂剂上的La网站。修正后的氧化物离子电导率由于捕获效应而大大降低，最终与实验电导率合理一致。
Interstitial oxide-ion conduction in tetragonal scheelite-structured oxides has theoretically been analyzed using first-principles calculations, taking lanthanum niobate (t-LaNbO4) as a model system. In the crystal, two interstitial sites of oxide ions were identified by exhaustive structural optimizations, which are located between two NbO4 tetragonal units to form an Nb2O9 unit. Among the four elementary paths found by the nudged elastic band method, the three common paths enable interstitial oxide ions to migrate over a long range both in the ab-plane and along the c-axis, leading to the almost isotropic oxide-ion conductivity. However, the oxide-ion conductivities estimated on the basis of the kinetic Monte Carlo method were much higher than the reported experimental values. The apparent activation energies were also different, ∼0.4 eV in the estimated conductivities vs. ∼0.9 eV in the experimental conductivities. As a result of additional evaluation of the trapping effect by dopants, interstitial oxide ions were found to be strongly trapped by W dopants on La sites. The corrected oxide-ion conductivity was drastically reduced by the trapping effect, finally to be in reasonable agreement with the experimental conductivities.
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影响因子：
3.7
作者：
K. Toyoura;Y. Koyama;A. Kuwabara;F. Oba;I. Tanaka
通讯作者：
K. Toyoura;Y. Koyama;A. Kuwabara;F. Oba;I. Tanaka
影响因子：
1.1
作者：
M. Yashima
通讯作者：
M. Yashima
影响因子：
8.6
作者：
Bechade, Emilie;Masson, Olivier;Champion, Eric
通讯作者：
Champion, Eric
受主掺杂焦磷酸锡质子电导率的第一性原理研究
DOI：
10.1021/acs.jpcc.6b12532
发表时间：
2017
期刊：
Physical Chemistry C
影响因子：
--
作者：
K. Toyoura;J. Terasaka;A. Nakamura;K. Matsunaga
通讯作者：
K. Matsunaga