First-principles study of oxygen-deficient LaNiO3 structures
First-principles study of oxygen-deficient LaNiO3 structures
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DOI：
10.1103/physrevb.92.144102
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发表时间：
2015-10-06
影响因子：
3.7
通讯作者：
Ismail-Beigi, Sohrab
中科院分区：
文献类型：
--
作者：
Malashevich, Andrei;Ismail-Beigi, Sohrab
我们描述了LaNiO3中氧空位性质的第一性原理计算结果。我们考虑了孤立的氧空位、对空位和有限浓度下形成LaNiO3缺氧相的空位。我们解决的关键电子结构问题是氧空位是否以及在多大程度上充当费米能级（移动和导电电子态）的电子供体。更一般地说，我们描述了如何基于电子结构计算来量化金属系统中的局域点缺陷向费米能级提供电子的程度，而不是在局域缺陷状态中捕获电子的程度。对于LaNiO3，我们发现氧空位不会产生移动载流子，而是使相邻的两个Ni位点变成Ni2+阳离子。在能量上，我们计算了氧空位的形成能和扩散势垒。在结构上，我们发现空位对倾向于形成在Ni阳离子的相对两侧，沿着伪轴对齐。在空位浓度有限的情况下，我们计算了空位浓度对LaNiO3晶格参数的依赖关系，为实验测定LaNiO3和LaNiO3薄膜中的氧含量提供了可靠的数据。
We describe the results of first-principles calculations of the properties of oxygen vacancies in LaNiO3. We consider isolated oxygen vacancies, pairs of vacancies, and vacancies at finite concentrations that form oxygen-deficient phases of LaNiO3. The key electronic structure question we address is whether and to what extent an oxygen vacancy acts as an electron donor to the Fermi level (mobile and conducting electronic states). More generally, we describe how one can quantify, based on electronic structure calculations, the extent to which a localized point defect in a metallic system donates electrons to the Fermi level compared to trapping electrons in localized defect states. For LaNiO3, we find that an oxygen vacancy does not create mobile carriers but instead makes the two Ni sites adjacent to it turn into Ni2+ cations. Energetically, we compute the formation energy and diffusion barrier for oxygen vacancies. Structurally, we show that pairs of vacancies prefer to form on opposite sides of a Ni cation, aligning along a pseudocubic axis. For finite concentrations of vacancies, we compute the dependence of the LaNiO3 lattice parameters on the vacancy concentration to provide reliable data for experimental determination of the oxygen content in LaNiO3 and LaNiO3 thin films.