2012 Fiscal Year Final Research Report
Study on physical properties of europium monoxide as a ferromagnetic semiconductor at room temperature
| Project/Area Number |
22340107
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Institute for Molecular Science |
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Principal Investigator |
KIMURA Shin-ichi 分子科学研究所, 極端紫外光研究施設, 准教授 (10252800)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Hidetoshi 名古屋工業大学, 工学研究科, 助教 (10548960)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 強磁性半導体 / 酸化ユーロピウム / 電子構造 / シンクロトロン放射 / 光電子分光 / 逆光電子分光 / 赤外分光 |
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| Research Abstract |
Europium monoxide EuO is a typical ferromagnetic semiconductor. The ferromagnetic transition temperature (Curie temperature, T_C) is increased from ~70 K to ~150 K or higher by electron doping and lattice contraction owing to Eu-excess and substitution of divalent Eu ions to trivalent ions with smaller ionic radius such as La or Gd. The origin has been discussed to be the hybridization between the Eu 4f and O 2p, the indirect exchange interaction between 4f electrons mediated by carriers, and/or a magnetic polaron effect. In this study, we succeeded to control separately the hybridization effect and the indirect exchange interaction by changing the thickness of films and carrier doping, respectively. The T_C of EuO is concluded to be determined by the combination of these interactions.
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[Journal Article] Atomic and electronic structure of ultrathin Bi(111) films grown on Bi_2Te_3(111) substrates: Evidence for a strain-induced topological phase transition2012
Author(s)
T. Hirahara, N. Fukui, T. Shirasawa, M. Yamada, M. Aitani, H. Miyazaki, M. Matsunami, S. Kimura, T. Takahashi, S. Hasegawa, K. Kobayashi
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Journal Title
Phys. Rev. Lett.
Volume: 109
Pages: 227401 (5 pages).
DOI
Peer Reviewed
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[Journal Article] Warping effects in the band and angular-momentum structures of the topological insulator Bi_2Te_32011
Author(s)
W. Jung, Y. Kim, B. Kim, Y. Koh, Chul Kim, M. Matsunami, S. Kimura, M. Arita, K. Shimada, J. H. Han, J. Kim, B. Cho, C. Kim
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Journal Title
Phys. Rev.
Volume: B 84
Pages: 245435 (6 pages)
DOI
Peer Reviewed
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[Journal Article] Nodeless superconducting gap in A_xFe_2Se_2 (A = K, Cs) revealed by angle-resolved photoemission spectroscopy2011
Author(s)
Y. Zhang, L. X. Yang, M. Xu, Z. R. Ye, F. Chen, C. He, H. C. Xu, J. Jiang, B. P. Xie, J. J. Ying, X. F. Wang, X. H. Chen, Jiangping Hu, M. Matsunami, S. Kimura, D. L. Feng
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Journal Title
Nat. Mater.
Volume: 10
Pages: 273-277
DOI
Peer Reviewed
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