坂井 延寿 助教

坂井 延寿（さかい えんじゅ）
博士（理学）
特任助教
〒113-8656 東京都文京区本郷7-3-1
東京大学 環境安全研究センター TEL 03-5841-2324, FAX 03-5841-2324
E-mail: e_sakaiesc.u-tokyo.ac.jp

個人ページ：

略歴

学歴
1999年3月麻布高等学校卒業
2004年3月東京大学理学部化学科 卒業
2006年3月東京大学理学系研究科化学専攻修士課程 修了
2009年年3月東京大学理学系研究科化学専攻博士課程 単位取得退学
2010年4月同博士課程修了 博士（理学）取得
研究題目「遷移金属ドープ二酸化チタンの室温強磁性発現機構の解明」
指導教官：長谷川哲也 教授

職歴
2007年4月日本学術振興会特別研究員（DC2)
2009年4月神奈川科学技術アカデミー 常勤準研究員
2010年4月東京大学工学系研究科 技術補佐員 （尾嶋研究室）
2010年6月同 特任研究員
2012年4月高エネルギー加速器研究機構物質構造科学研究所 （組頭グループ）博士研究員
2015年4月東京大学工学系研究科 特任研究員 （堂免・嶺岸研究室）
2016年11月東京大学 環境安全研究センター 特任助教
2020年2月東京大学 環境安全研究センター 助教
現在に至る

研究歴
2015年4月
〜2016年11月		 東京大学化学システム工学専攻において
可視光水分解光触媒を目指した酸窒化物薄膜の作製とその電子状態評価に従事
(E. Sakai et al., Nanoscale 8, 18893-18896 (2016).)
2010年4月
〜2015年3月		 東京大学、高エネルギー加速器研究機構において
光電子分光法を用いた酸化物薄膜の金属絶縁体転移に関する研究に従事
E. Sakai et al., Phys. Rev. B 84, 1951432 (2011).
E. Sakai et al., Phys. Rev. B 87, 075132 (2013).
E. Sakai et al., Appl. Phys. Lett. 104, 171609 (2014).
2009年4月
〜2010年3月		 神奈川科学技術アカデミーにおいて
青色LED用新規透明電極の開発に従事
2006年4月
〜2009年3月		 同博士課程（指導教員：長谷川哲也教授）
遷移金属ドープ二酸化チタンにおける室温強磁性発現機構に関する研究に従事
E. Sakai et al., Appl. Phys. Express 3, 043001 (2010).
E. Sakai et al., J. Mag. Mag. 333, 130 (2013).
2003年4月
〜2006年3月 東京大学理学部化学科・理学系研究科化学専攻修士課程（指導教員：太田俊明教授）
深さ分解磁気円二色性（XMCD）を用いた磁性薄膜の研究に従事
K. Amemiya, E. Sakai et al., Phys. Rev. B 71, 214420 (2005).
K. Amemiya, E. Sakai et al., Phys. Rev. B 72, 201404(R) (2005).

査読付き原著論文

1. E. Sakai, N. Nagamura, J. Liu, T. Hisatomi, T. Yamada, K. Domen and M. Oshima,
"Investigation of the enhanced photocathodic activity of La5Ti2CuS5O7 photocathodes in H2 evolution by synchrotron radiation nanospectroscopy." Nanoscale 8, 18893-18896 (2016).

2. T. Suetsugu, Y. Shimazu, T. Tsuchiya, M. Kobayashi, M. Minohara, E. Sakai, K. Horiba, H. Kumigashira, and T. Higuchi,
"Metal-Insulator Transition of Valence-Controlled VO2 Thin Film Prepared by RF Magnetron Sputtering Using Oxygen Radical" Jpn. J. Appl. Phys. 55, 06GJ11 (2016).

3. M. Kitamura, K. Horiba, M. Kobayashi, E. Sakai, M. Minohara, T. Mitsuhashi, A. Fujimori, T. Nagai, H. Fujioka, and H. Kumigashira,
“Spatial distribution of transferred charges across the heterointerface between perovskite transition metal oxides LaNiO3 and LaMnO3” Appl. Phys. Lett. 108, 111603 (2016).

4. K. Horiba, M. Kitamura, K. Yoshimatsu, M. Minohara, E. Sakai, M. Kobayashi, A. Fujimori, and H. Kumigashira,
“Isotropic Kink and Quasiparticle Excitations in the Three-Dimensional Perovskite Manganite La0.6Sr0.4MnO3” Phys. Rev. Lett. 116, 076401 (2016).

5. H. Suzuki, G. Q. Zhao, K. Zhao, B. J. Chen, M. Horio, K. Koshishi, J. Xu, M. Kobayashi, M. Minohara, E. Sakai, K. Horiba, H. Kumigashira, B. Gu, S. Maekawa, Y. J. Uemura, C. Q. Jin, and A. Fujimori,
"Fermi Surfaces and p-d Hybridization in the Diluted Magnetic Semiconductor Ba1-xKx(Zn1-yMny)2As2 Studied by Soft X-ray Angle Resolved Photoemission Spectroscopy" Phys. Rev. B 92, 235120 (2015).

6. M. Kobayashi, K. Yoshimatsu, E. Sakai, M. Kitamura, K. Horiba, A. Fujimori, and H. Kumigashira,
“Origin of the anomalous mass renormalization in metallic quantum well states of strongly correlated oxide SrVO3” Phys. Rev. Lett. 115, 076801 (2015).

7. T. Suetsugu, Y. Shimazu, T. Tsuchiya, M. Kobayashi, E. Sakai, K. Horiba, H. Kumigashira,and T. Higuchi,
“Electronic structure for b-axis orientated of VO2 thin film with mixed-valent state by soft X-ray spectroscopy” J. Phys. Soc. Jpn. 84, 064715 (2015).

8. M. Kitamura, M. Kobayashi, E. Sakai, R. Takahashi, M. Lippmaa, K. Horiba, H. Fujioka, and H. Kumigashira,
“Determination of band diagram for a p-n junction between Mott insulator LaMnO3 and band insulator Nb:SrTiO3”Appl. Phys. Lett. 106, 061605 (2015).

9. K. Usui, S. Yamaguchi, N. Suzuki, Y. Shimazu, E. Sakai, M. Kobayashi, K. Horiba, H. Kumigashira, and T. Higuchi,
“Electronic Structure of Ti1-xFexO2-δ Thin Film with Oxygen Vacancies Probed by Soft-X-RaySpectroscopy”J. Jpn. Appl. Phys. 54, 06FJ04?1-5 (2015).

10. T. Higuchi, T. Owaku, Y. Iida, E. Sakai, M. Kobayashi, H. Kumigashira,
“Proton conduction of BaCe0.90Y0.10O3-d thin film with lattice distortion”Solid State Ionics 270, 1-5 (2015).

11. H. Wadati, J. Okamoto, M. Garganourakis, V. Scagnoli, U. Staub, E. Sakai, H. Kumigashira, T. Sugiyama, E. Ikenaga, M. Nakamura, M. Kawasaki, and Y. Tokura,
Orbital correlations and dimensional crossover in epitaxial Pr0.5Ca0.5MnO3/La0.5Sr0.5MnO3superlattices New J. Phys. 16, 073044 (2014).

12. G. Shibata, K. Yoshimatsu, E. Sakai, V. R. Singh, V. K. Verma, K. Ishigami, T. Harano, T. Kadono, Y. Takeda, T. Okane, Y. Saitoh, H. Yamagami, A. Sawa, H. Kumigashira, M. Oshima, T. Koide, and A. Fujimori,
Thickness-dependent ferromagnetic metal-to-paramagnetic insulator transition in La0.65Sr0.4MnO3thin films studies by x-ray magnetic circular dichroism Phys. Rev. B 89, 235123 (2014).

13. T. Inoue, T. Okumura, Y. Shimazu, E. Sakai, H. Kumigashira and T. Higuchi,
Electrical Conductivity of Sc-doped TiO2 Thin Film Prepared by RF Magnetron Sputtering Jpn. J. Appl. Phys. 53, 06JG03 (2014).

14. Y. Shimazu, T. Okumura, E. Sakai, H. Kumigasira, M. Okawa, T. Saitoh and T. Higuchi,
Growth of TiO2 Thin Film by RF Magnetron Sputtering Using Oxygen Radical and Ti-Metal Jpn. J. Appl. Phys. 53, 06JG01(2014).

15. Y. Shimazu, T. Okumura, A. Shimada, K. Tanabe, K. Tokiwa, E. Sakai, H. Kumigasira and T. Higuchi,
Electronic Structure of V2O3 Thin Film Prepared by RF Magnetron Sputtering using Oxygen Radical and V-Metal J pn. J. Appl. Phys. 53, 06JG05 (2014).

16. E. Sakai, K. Yoshimatsu, M. Tamamitsu, K. Horiba, A. Fujimori, M. Oshima, and H. Kumigashira
Bandwidth-controlled metal-insulator transition in epitaxial PrNiO3 ultrathin films induced by dimensional crossover, Appl. Phys. Lett. 104, 171609 (2014).

17. S. Toyoda, T. Namiki, E. Sakai, K. Nakata, M. Oshma, and H. Kumigashira,
Chemical-state-resolved depth profiles of Al/Pr0.7Ca0.3MnO3 J. Appl. Phys. 114, 243711 (2013).

18. K. Yoshimatsu, H. Wadati, E. Sakai, T. Harada, Y. Takahashi, G. Shibata, K. Ishigami, T. Kadono, T. Koide, T. Sugiyama, E. Ikenaga, H. Kumigashira, M. Lippmaa, M. Oshima, and A. Fujimori,
Spectroscopic studies on the electronic and magnetic states of Co-doped perovskite manganite Pr0.8Ca0.2Mn1-yCoyO3 thin films, Phys. Rev. B 88, 174423 (2013).

19. K. Yoshimatsu, E. Sakai, M. Kobayashi, K. Horiba, T. Yoshida, A. Fujimori, M. Oshima, and H. Kumigashira,
Determination of the surface and interface phase shifts in metallic quantum well structures of perovskite oxides Phys. Rev. B 88, 115308 (2013).

20. K. Nogami, K. Yoshimatsu, H. Mashiko, E. Sakai, H. Kumigashira, O. Sakata, T. Oshima, and A. Ohtomo,
Epitaxial synthesis and electronic properties of double-perovskite Sr2TiRuO6 films Appl. Phys. Express 6, 105502 (2013).

21. H. Suzuki, T. Yoshida, S. Ideta, G. Shibata, K. Ishigami, T. Kadono, A. Fujimori, M. Hashimoto, D. H. Lu, Z. ?X. Shen, K. Ono E. Sakai, H. Kumigashira, M. Matsuno, and T. Sasagawa,
Absence of superconductivity in the hole-doped Fe pnictide Ba(Fe1-xMnx)2As2: Photoemission and x-ray absorption spectroscopy studies, Phys. Rev. B 88, 100501(R) (2013).

22.T. Yokobori, M. Okawa, K. Konishi, R. Takei, K. Katayama, S. Oozono, T. Shinmura, T. Okuda, H. Wadati, E. Sakai, K. Ono, H. Kumigashira, M. Oshima, T. Sugiyama, E. Ikenaga, N. Hamada, and T. Saitoh,
Electronic structure of hole-doped delafossite oxides CuCr1-xMgxO2, Phys. Rev. B 87, 195124 (2013).

23. E. Sakai, M. Tamamitsu, K. Yoshimatsu, S. Okamoto, K. Horiba, M. Oshima, and H. Kumigashira
Gradual localization of Ni 3d states in LaNiO3 ultrathin films induced by dimensional crossover, Phys. Rev. B 87, 075132 (2013).

24. E. Sakai, K. Amemiya, A. Chikamatsu, Y. Hirose, T. Shimada, and T. Hasegawa,
X-ray absorption and magnetic circular dichroism characterization of Fe-doped TiO2-? thin films, J. Mag. Mag. 333, 130 (2013).

25. T. Okumura, T. Inoue, Y. Tasaki, E. Sakai, H. Kumigashira, and T. Higuchi,
Electronic Structure of SrTi0.99Sc0.01O3 Thin Film by High-Resolution Soft-X-Ray Spectroscopy, J. Phys. Soc. Jpn. 81, 094705 (2012).

26. E. Sakai, K. Yoshimatsu, K. Shibuya, H. Kumigashira, E. Ikenaga, M. Kawasaki, Y. Tokura, and M. Oshima,
Competition between instabilities of Peierls transition and Mott transition in W-doped VO2 thin films, Phys. Rev. B 84, 195132 (2011).

27. J. Ohkubo, Y. Hirose, E. Sakai, S. Nakao, T. Hitosugi, and T. Hasegawa,
Wet Etching of TiO2-Based Precursor Amorphous Films for Transparent Electrodes, Jpn. J. Appl. Phys. 50, 018002 (2011).

28.E. Sakai, A. Chikamatsu, Y. Hirose, T. Shimada, and T. Hasegawa,
Transport and magnetic properties of anatase TiO2 codoped with Fe and Nb, Appl. Phys. Express 3, 043001 (2010).

29. J. Miyawaki, D. Matsumura, H. Abe, T. Ohtsuki, E. Sakai, K. Amemiya, and T. Ohta,
Perpendicular magnetic anisotropy associated with strain relaxation in Ru/Co/Ru(0001): Anomalous relation of atomic and magnetic structures, Phys. Rev. B 80, 020408(R) (2009).

30. H. Abe, K. Amemiya, D. Matsumura, J. Miyawaki, E. O. Sako, T. Ohtsuki, E. Sakai, and T. Ohta,
Anomalous magnetic phases in Fe/Cu(001) ultrathin films induced by CO adsorption, Phys. Rev. B, 77 054409 (2008).

31. K. Amemiya, E. Sakai, D. Matsumura, H. Abe, and T. Ohta,
Anomalous behavior of satellite features at the surface and interface in the Ni L-edge x-ray absorption spectra, Phys. Rev. B 72, 201404(R) (2005).

32. K. Amemiya, E. Sakai, D. Matsumura, H. Abe, T. Ohta, and T. Yokoyama
Spin-reorientation transition of Ni/Cu (100) and CO/Ni/Cu (100): Separation of the surface and bulk components of the X-ray magnetic circular dichroism spectrum, Phys. Rev. B, 71, 214420 (2005).

国際学会予稿

1. Y. Wakabayashi, H. Maeda, T. Kimura, O. Sakata, E. Sakai, and H. Kumigashira,
“Microscopic Observation of Degradation of LaNiO3 Ultrathin Films Caused by Air Exposure” e-Journal of Surface Science and Nanotechnology 14, 14 (2016).

2. K. Usui, T. Okumura, E. Sakai, H. Kumigashira, and T. Higuchi,
“Structural and electronic properties of anatase Ti1?xFexO2?δ thin film prepared by RF magnetron sputtering” J. Phys.: Conf. Ser. 502, 012001 (2014).

3. T. Maruyama, T. Ohtsuki, E. Sakai, H. Abe, T. Shimada, T. Hasegawa, S-I. Nagamatsu, and T. Fujikawa,
“Multiple-scattering approach to Ti L2,3-edge XMCD analyses for Co doped TiO2” J. Phys.: Conf. Ser. 190 012018 (2009).

4. H. Abe, K. Amemiya, J. Miyawaki, E. O. Sako, M. Sakamaki, D. Matsumura, T. Ohtsuki, E. Sakaiand T. Ohta
"CO Adsorption Effects on the Magnetism and Surface Structure of Fe/Cu(001)" e-Journal of Surface Science and Nanotechnology, 6, 233 (2008).

5. H.Abe, K.Amemiya, D.Matsumura, T.Ohtsuki, E.Sakai, T.Yokoyama, and T.Ohta,
"Depth-resolved XMCD application to Fe/Ni/Cu(001) films" AIP Conf. Proc. 882, 384 (2007).

6. J.Miyawaki, D.Matsumura, H.Abe, T.Otsuki, E.Sakai, K.Amemiya, and T.Ohta,
"Spin Reorientation Transition in Ultrathin Co Films on Ru(0001) Induced by Ru Capping ", AIP Conf. Proc. 882, 505 (2007).