Daelman Nathan, Hegner Franziska Simone, Rellán-Piñeiro Marcos, Capdevila-Cortada Marçal, García-Muelas Rodrigo, López Núria
Institute of Chemical Research of Catalonia, ICIQ, The Barcelona Institute of Science and Technology, BIST, Av. Països Catalans 16, 43007 Tarragona, Spain.
J Chem Phys. 2020 Feb 7;152(5):050901. doi: 10.1063/1.5138484.
The physical and chemical properties of oxides are defined by the presence of oxygen vacancies. Experimentally, non-defective structures are almost impossible to achieve due to synthetic constraints. Therefore, it is crucial to account for vacancies when evaluating the characteristics of these materials. The electronic structure of oxygen-depleted oxides deeply differs from that of the native forms, in particular, of reducible metal oxides, where excess electrons can localize in various distinct positions. In this perspective, we present recent developments from our group describing the complexity of these defective materials that highlight the need for an accurate description of (i) intrinsic vacancies in polar terminations, (ii) multiple geometries and complex electronic structures with several states attainable at typical working conditions, and (iii) the associated dynamics for both vacancy diffusion and the coexistence of more than one electronic structure. All these aspects widen our current understanding of defects in oxides and need to be adequately introduced in emerging high-throughput screening methodologies.
氧化物的物理和化学性质由氧空位的存在所定义。在实验中，由于合成限制，几乎不可能获得无缺陷的结构。因此，在评估这些材料的特性时考虑空位至关重要。贫氧氧化物的电子结构与原生形式有很大不同，特别是对于可还原金属氧化物，其中多余的电子可以定域在各种不同位置。从这个角度出发，我们展示了我们团队最近的进展，描述了这些有缺陷材料的复杂性，突出了准确描述以下几点的必要性：（i）极性终端中的本征空位；（ii）在典型工作条件下可获得多种状态的多种几何结构和复杂电子结构；（iii）空位扩散以及多种电子结构共存的相关动力学。所有这些方面拓宽了我们目前对氧化物中缺陷的理解，并且需要在新兴的高通量筛选方法中得到充分介绍。
