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Unusually Large Thermopower Change from +330 to -185 mu V K-1 of Brownmillerite SrCoO2.5
| Title: | Unusually Large Thermopower Change from +330 to -185 mu V K-1 of Brownmillerite SrCoO2.5 |
| Authors: | Yang, Qian Browse this author | | Lee, Joonhyuk Browse this author | | Feng, Bin Browse this author | | Ikuhara, Yuichi Browse this author | | Kim, Gowoon Browse this author | | Cho, Hai Jun Browse this author | | Jeen, Hyoungjeen Browse this author | | Ohta, Hiromichi Browse this author →KAKEN DB |
| Keywords: | thermopower | | brownmillerite SrCoO2.5 | | epitaxial film | | pulsed laser deposition | | electronic structure |
| Issue Date: | 28-Jul-2020 |
| Publisher: | American Chemical Society |
| Journal Title: | ACS Applied Electronic Materials |
| Volume: | 2 |
| Issue: | 7 |
| Start Page: | 2250 |
| End Page: | 2256 |
| Publisher DOI: | 10.1021/acsaelm.0c00427 |
| Abstract: | Strontium cobalt oxide (SrCoO2.5) has recently attracted increasing attention as its optoelectronic and magnetic properties can be widely controlled using electrochemical oxidation/protonation at room temperature in air. To utilize the versatile properties of SrCoO2.5, it is essential to evaluate the location of the Fermi energy (E-F) in the electronic structure, which is sensitive to the oxidation state of the Co ions. Here, we show that thermopower is an excellent measure for analyzing the E-F in SrCoO2.5 epitaxial films. The lattice mismatch causes grain size reduction, which induces a slight increase in the oxidation state of the Co ions due to additional adsorbed oxygen. Although X-ray spectroscopy analyses reveal that the difference of the oxidation state of the Co ions among the samples is small, an unusually large change in thermopower from +330 mu V K-1 (lattice-matched) to -185 mu V K-1 (lattice-mismatched) is observed in the samples due to shifts in the E-F to the lower energy side. The present results demonstrate the excellent sensitivity of thermopower measurements for analyzing the location of E-F in the electronic structure of SrCoO(2.3 )in a practically usable environment. |
| Rights: | This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Electronic Materials, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acsaelm.0c00427 . |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/82293 |
| Appears in Collections: | 電子科学研究所 (Research Institute for Electronic Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 太田 裕道
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