Directing Oxygen Vacancy Channels in SrFeO2.5 Epitaxial Thin Films

作者：Khare Amit; Lee Jaekwang; Park Jaeseoung; Kim Gi Yeop; Choi Si Young; Katase Takayoshi; Roh Seulki; Yoo Tae Sup; Hwang Jungseek; Ohta Hiromichi; Son Junwoo; Choi Woo Seok^*

来源：ACS Applied Materials & Interfaces, 2018, 10(5): 4831-4837.

DOI：10.1021/acsami.7b17377

• brownmillerite
• epitaxial thin film
• electronic structure
• crystalline orientation
• optical spectroscopy

Transition-metal oxides (TMOs) with brown-millerite (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-SrFeO2.5 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-SrFeO2.5 thin films. The results demonstrate a strong correlation between crystallographic orientations, electronic structures, and ionic motion in the BM structure.

• 出版日期2018-2-7