Department of Physics, Indian Institute of Science Education of Research (IISER) , Bhopal 462 066, India.
Department of Physics, Pusan National University , Pusan 46241, Republic of Korea.
ACS Appl Mater Interfaces. 2018 Feb 7;10(5):4831-4837. doi: 10.1021/acsami.7b17377. Epub 2018 Jan 23.
Transition-metal oxides (TMOs) with brownmillerite (BM) structures possess one-dimensional oxygen vacancy channels (OVCs), which play a key role in realizing high ionic conduction at low temperatures. The controllability of the vacancy channel orientation, thus, possesses a great potential for practical applications and would provide a better visualization of the diffusion pathways of ions in TMOs. In this study, the orientations of the OVCs in BM-SrFeO are stabilized along two crystallographic directions of the epitaxial thin films. The distinctively orientated phases are found to be highly stable and exhibit a considerable difference in their electronic structures and optical properties, which could be understood in terms of orbital anisotropy. The control of the OVC orientation further leads to modifications in the hydrogenation of the BM-SrFeO thin films. The results demonstrate a strong correlation between crystallographic orientations, electronic structures, and ionic motion in the BM structure.
具有尖晶石（BM）结构的过渡金属氧化物（TMO）具有一维氧空位通道（OVC），在实现低温下的高离子传导方面起着关键作用。因此，空位通道取向的可控性具有很大的实际应用潜力，并将为 TMO 中离子的扩散途径提供更好的可视化效果。在这项研究中，BM-SrFeO 中的 OVC 取向沿着外延薄膜的两个晶体学方向稳定。发现明显取向的相非常稳定，并且在电子结构和光学性质方面存在显著差异，可以根据轨道各向异性来理解。OVC 取向的控制进一步导致 BM-SrFeO 薄膜的加氢作用发生变化。结果表明，在 BM 结构中，晶体取向、电子结构和离子运动之间存在强烈的相关性。
