2021 Fiscal Year Final Research Report
Skewed electronic band structure of ferroelectric oxide induced by the electric polarization
Project/Area Number |
19K05271
|
Research Category |
Grant-in-Aid for Scientific Research (C)
|
Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 29020:Thin film/surface and interfacial physical properties-related
|
Research Institution | Okayama University |
Principal Investigator |
Kano Jun 岡山大学, 自然科学学域, 准教授 (50375408)
|
Project Period (FY) |
2019-04-01 – 2022-03-31
|
Keywords | 強誘電体 / バンド構造 / 角度分解光電子分光法 / 薄膜 |
Outline of Final Research Achievements |
Angle-resolved hard x-ray photoemission spectroscopy (AR-HAXPES) has been performed on a skewed electronic structure in ferroelectric thin films. The slope of the skewed band could be changed by switching the polarization. In our experiment, an electronic structure skewed by the electric polarization of ferroelectric is revealed by the binding energy shift of atomic orbitals. All atomic orbitals show similar behaviors, but the magnitude of the energy shift is different. We attributed the electric polarization in the ion crystal to the atomic contribution. Born effective charges, which are different from nominal ionic charges, are defined by the actual amplitude of the polarization divided by the ionic displacement. We found that the magnitude of the energy shift of each atomic orbital has a good correlation with the Born effective charge. These findings lead to a better understanding of the origin of electric polarization.
|
Free Research Field |
固体物理学
|
Academic Significance and Societal Importance of the Research Achievements |
スマートフォンなどに用いられるコンデンサーの基幹材料である強誘電体は,電荷を蓄えられるだけでなく,ダイオードのような電気の流れ方をすることが最近わかってきた。その動作原理は,「傾斜したバンド構造」によるものと考えられてきたが,実証した例はなかった。我々は放射光を用いた実験により,初めて傾斜したバンド構造の直接観測に成功した。今回の成果により,強誘電体を用いた新しいデバイス開発の進展が期待される。
|