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渡部 行男(わたなべ  ゆきお) データ更新日:2019.07.26

教授 /  理学研究院 物理学部門 物性物理学


主な研究テーマ
量子微小物性A担当 (2010年以降、公式に量子微小物性B荒井准助教と別組織)

電子物性 特に 原子スケールの現象を物性に結合する試み。これを誘電体を中心にして行う。絶縁性と絶縁体中の伝導を原理的に見直し新しい立場を探す。
キーワード:原子スケール 絶縁性 誘電体 表面 量子効果
1995.08.
従事しているプロジェクト研究
特定領域研究 強誘電体薄膜の物性制御と次世代デバイスへの応用 計画班員
2000.08~2003.03, 代表者:奥山雅則 (領域代表), 大阪大学, 大阪大学 名古屋大学 九州大学 東京工業大学 .
研究業績
主要著書
1. Yukio Watanabe, Ferroelectric Thin Films - Basic and Device Physics in FerroelectricThin Films for Memory Application (Topics in Applied Physics 98), Springer, Physics of ferroelectric interface: Attempt at nanoferroelectric physics, 2005.06, (citation 5 2014.1).
主要原著論文
1. Y. Watanabe, Unidirectional bulk conduction and the anomalous temperature dependence of drift current under a trap-density gradient, Phys. Rev. B, 81, 195210, 2010.05, Nonlinear drift conduction under a trap-density gradient is mathematically formulated. Semianalytical and numerical solutions demonstrate bulk-induced unidirectional current flow, i.e., rectification. The present theory is in excellent agreement with various experimental J-V characteristics J: current density and V: applied voltage. At low V, the J-V characteristics are ohmic and bidirectional. As the injection increases, the J-V characteristics become nonlinear and exhibit unidirectionality under proper conditions. The major requirements for a large unidirectionality are the trap-density gradient G1, an intermediate V, and not too large trap-filling factor , which requires the presence of acceptorlike traps. The unidirectional J-V characteristics due to the difference in trap-filled-to-trap-free-limit voltage VTFL for forward and reverse bias markedly resemble the standard rectification. In addition, the trap-density gradient yields a positive T dependence of resistance for a proper set of parameters, evident JV1.5 characteristics, and a photovoltaic effect. The present results suggest that bulk conduction under trap-density gradient explains fractions of resistance switching and rectification phenomena. The semianalytical solutions are verified by numerical solutions and comparison with experiments. In particular, semianalytical solutions for shallow-trap case excellently fit the experimental data by three parameters in practice: two scaling factors and G..
2. M. Okano, Y. Watanabe, S. W. Cheong , Nonlinear positive temperature coefficient of resistance of Schottky contact on strained epitaxial BaTiO3 film,  Appl. Phys. Lett. 82(12), 1923-1925 (2003), 10.1063/1.1563061, 82, 12, 1923-1925, 2003.03.
3. 渡部 行男, J. G. Bednorz, A. Bietsch, Ch. Gerber, D. Widmer, A. Beck, S. J. Wind, Current-driven insulator-conductor transition and nonvolatile memory in chromium-doped SrTiO3 single crystals,  Appl. Phys. Lett.78 (23), 3738-3740 (2001)., 2001.06.
4. Y. Watanabe, M. Okano, Photodiode properties of epitaxial Pb(Ti,Zr)O3/SrTiO3 ferroelectric heterostructures,  Appl. Phys. Lett.78(13), 1906-1908 (2001), 2001.03.
5. Y. Watanabe, M. Okano, A. Masuda, Surface conduction on insulating BaTiO3 crystal suggesting an intrinsic surface electron layer,  Phys. Rev. Lett. 86 (2), 332-335 (2001)., 2001.01.
6. Y. Watanabe, Electrical transport through Pb(Zr,Ti)O3 pn and pp heterostructures modulated by bound charges at a ferroelectric surface: Ferroelectric pn diode,  Phys. Rev. B 59(17)11257-11266(1999)., 1999.12.
7. Y. Watanabe, Tunneling current through a possible all-perovskite oxide pn junction,  Phys. Rev. B57(10) (Rapid Commun.) R5563-R5566 (1998), 1998.03.
8. Y. Watanabe, Theoretical stability of the polarization in insulating-ferroelectric/semiconductor structures,  J. Appl. Phys. 83 (4), 2179-2193(1998), Erratum: J. Appl. Phys. 84(6), 3428 (1998), 1998.02.
9. Y. Watanabe, Theoretical stability of the polarization in a thin semiconducting ferroelectric,  Phys. Rev. B57(2), 789-804 (1998), 1998.01.
10. Y. Watanabe, Epitaxial all-perovskite ferroelectric field effect transistor with a memory retention,  Appl. Phys. Lett.66(14), 1770-1772 (1995), 1995.04.
11. Y. Watanabe, A reproducible memory effect in the leakage current of epitaxial
ferroelectrics/conductive perovskite hetero-structures,  Appl. Phys. Lett.66(1), 28-30 (1995), 1995.01.
12. Y. Watanabe, Ferroelectric/ (La,Sr)2CuO4 epitaxial hetero-structure and hysteretic diode property, Physica C235-240, 739-740 (1994), 1994.12.
13. Y. Watanabe, Y. Matsumoto, H. Kunitomo, M. Tanamura, E. Nishimoto, Crystallographic and electronic properties of epitaxial BaTiO3 film grown on conductive and insulating perovskite oxides,  Jpn J. Appl. Phys. 33(9B), 5182-5186 (1994), 1994.09.
14. Y. Watanabe, D.C. Tsui, J.T. Birmingham, N.P. Ong, J.M. Tarascon, Infrared reflectivity of single-crystal Bi2Mm+1ComOy (M= Ca, Sr, Ba; m=1, 2), Bi2Sr3Fe2O9.2 and Bi2Sr2MnO6.25 isomorphic to Bi-Cu-based high-Tc oxides,  Phys. Rev. B 43(4), 3026-3033 (1991)., 1991.11.
15. Y. Watanabe, Z.Z. Wang, S.A. Lyon, S.A. Lyon, D.C. Tsui, N.P. Ong, J.M. Tarascon, P.Barboux, Mid-Infrared reflectivity and ellipsometry measurements on single crystal YBa2Cu3O7 and Bi2Sr2CuO6+y,  Phys. Rev. B 40(10), 6884-6889 (1989)., 1989.10.
16. Y. Watanabe, J. Sasaki, Y. Kobayashi and T. Yoshitomi, Magneto-optical disc with alumina based oxide layer,  IEEE Trans. Mag-23(5), 2623-2625, 1987.11.
17. Y. Watanabe, T. Terasawa, On the excitation mechanism of the low-frequency upstream waves, J. Geophys. Res. 89(A8), 6623- 6630 (1984)., 1984.08.
18. Y. Watanabe, A. Nishida, Field line distortion and Joule heating by the Corotation Enforcement Currents in the Jovian Magneto-Ionosphere, J. Geophys. Res. 87(A10), 8111-8117 (1982)., 1982.10.
主要総説, 論評, 解説, 書評, 報告書等
1. Yukio Watanabe, Review of Resistance Switching of Ferroelectrics and Oxides in Quest for Unconventional Electronic Mechanisms, Ferroelectrics 349,190–209 (2007), citation 33(2015.5)被引用回数 は ISI (Web of Science) Google Scholar による被引用回数は43回(2015年), 2007.04, Resistance switching effects in perovskite oxides, which acquire recently intense interests
for the application to the resistance-random-access memories, are reviewed with
emphasis on paraelectric and ferroelectric oxides. We examine whether the switching
mechanism is the electric field effect or the current injection effect as well as the in
nanometer scale writing/reading/erasing. Based on these examinations, we search for
the traces of unconventional electronic switching, as opposed to thermal and defect
mechanisms that are considered responsible for the most results in the past..
2. 渡部, ナノ強誘電体のサイズ効果とは何か? — 極微小化から見る強誘電性基礎 —, 固体物理 (アグネ出版), 2003.02.
3. 渡部, 強誘電体薄膜の集積メモリー応用とその物理的基礎に向けて, 固体物理 (アグネ出版), 1998.03.
4. 渡部, ペロブスカイト系強誘電体薄膜ヘテロ構造におけるメモリー効果, 応用物理学会誌, 1996.03.
5. Y. Watanabe, Study of an epitaxial ferroelectrics /semiconductor /insulator structure using perovskite oxides for application to the field effect transistor, Extended Abstracts of Solid State Device and Materials conf.94 SSDM'94, (Yokohama, 1994,Aug), pp784-786, 1994.08.
主要学会発表等
1. Y. Watanabe, Renovation of Electrostatics of Ferroelectrics Liberating Ferroelectricity from Established Restrictions (招待講演), 14th European Meeting on Ferroelectricity(EMF) (2019 IEEE ISAF-ICE-EMF-IWPM-PFM Joint Conference内), 2019.07, Ultimate smallest sizeand domainconfigurationsof ferroelectricshave beenconsideredto be severely restricted by the electric field from the spontaneous polarization (PS).This has been a conventional principlefor nano-ferroelectrics, insulator/ferroelectric interfacesin thin film applications, ferroelectric surface, and some kinds of domains (Fig.1), imposing fundamental limitations.

Decades ago, we showed for the first time1
1) spontaneous formation of a free electron/hole (e-/h+) layer generally at thediscontinuity of PS(Fig.1),
2) its thermodynamic meta-stability, and
3)its drastic impact on the reduction of the aforementioned restrictionsand limitations.

Thepredictions 1)2)1were proved by the firstexperimental discovery of this free e-/h+layer2and are supported by numerous recent works reporting possiblee-/h+layer at domain boundariespresumably due to PS

The extreme resistanceagainst the size limitationsgiven by the e-/h+ layer1mentioned in 3)also begins to be confirmed by ab initio theories3,4in specialferroelectrics named as “hyper-ferroelectrics”.3,4

We will show that prototypical ferroelectrics BaTiO3and PbTiO3exhibit hyper-ferroelectricity by ab initiocalculation for the first time, based on an extensive study of functionals.5,6

Furthermore, we will present an easy-to-use-by-everybody approximate material-independent algebraic formula to predict the ultimatesize, which will be examined by ab initiocalculations and experiments. This shall show that hyper-ferroelectricityis a propertyof generalferroelectrics.

Using these results, we will clarify the origins of instabilities of encounteringdomains and their e-/h+layer,considering also charge injection and defect formation as observed in resistance-switching in general metal oxides.

In addition, the renowned electron layer at LaAlO3/SrTiO3will be shown to be significantly contributed by the present mechanism.7

References
[1]Y. Watanabe, Phys. Rev.B57, 789 (1998); Y. Watanabe and A. Masuda, Integrated Ferroelectrics27, 51 (1999).
[2]Y. Watanabe et al., Phys. Rev. Lett.86, 332 (2001).
[3] K. Garrity et al.,Phys. Rev. Lett. 112, 127601 (2014).
[4]S. Liu andR. E. Cohen, J. Phys. 29, 244003 (2017).
[5] Y. Watanabe, J. Chem. Phys.148, 194702 (2018),
[6]Y. Watanabe, Comp. Mat.Sci.158, 315 (2019),
[7] Y. Watanabe, Phys. Rev.B 99, 064107 (2019)..
2. Y. Watanabe, D. Matsumoto, Y. Urakami and M. Okano, Unification of conductions at domain-boundaries, SrTiO3/LaAlO3 & free surface for size effect and domain theories    (招待講演), E-MRS (European Meeting of Materials Research Society), 2018.09, Conduction at domain-boundaries, ferroelectric/insulator like SrTiO3/LaAlO3 (STO/LAO), and free surface is a hot topic in physics of ferroics. Although, as predicted*, these conductions are often attributed to polarization discontinuity of spontaneous polarization Ps, the importance of the extrinsic origins as defects, impurities, and field-induced defects have been established, and emphasized by Szot and Roleder.**
Indeed, these mechanisms exist in most of conduction phenomena. In STO/LAO the defects and intermixtures are unavoidable because of the growth at high temperature in vacuum. In the low-mobility and artificially-formed domain-boundaries, the pinning by defects and high-field-induced defects should exist, respectively; the domain boundaries are formed along the path of the high field. Moreover, most of the clean surfaces of metal oxides are prepared through the annealing in vacuum that forms defects such as oxygen vacancy.
On the other hand, the Ps–induced conduction at domain boundaries and ferroelectric/insulator boundary was earlier predicted* to show its important influence on size effect and domains. Therefore, the rigorous examinations whether Ps is the dominant origin of these conductions are of primary importance. The intrinsicness of Ps–induced conduction in the view of sample preparation, measurement methods and conduction characteristics will be discussed together with their implications.
* Watanabe,PRB57,789(1998);PRL 86,332(2001),**IMF Abst. 245 (2017)..
3. Y. Watanabe, D. Matsumoto, Y. Urakami and M. Okano, Polarization-Discontinuity Conductions at Domain Boundaries, Interfaces & Surfaces: Unification and Implications for Domain, Size Effects & Hyper-ferroelectricity   (招待講演)        , 2018 ISAF-FMA-AMF-AMEC-PFM Joint Conference IFAAP2018, 2018.05, Conductions at charged domain boundaries and the interface of ferroelectrics are much interested [1-4]. The conduction at the interface of an incipient ferroelectric SrTiO3(STO) and LaAlO3(LAO), are likely due to adjacent chemical doping [5], and defects [5,6] assisted by ferroelectric polarization [7-9]. Here, the metallization of STO by La doping [10,11] or oxygen vacancy [6] and modulation doping by adjacent layer [12] were established long ago, and intediffusion and oxygen vacancy are unavoidable when formed in vacuum at high temperature [5].
Therefore, both conductions at domain boundaries and STO/LAO are considered as polarization-discontinuity conductions or polarization-discontinuity-assisted conductions predicted theoretically and experimentally (Fig. 1) [13, 14]. The application of these conductions to electronics is exceptionally challenging owing to the competitions with other candidates like resistance switching [15] and Si that can have higher electron/hole mobility than STO/LAO at 4 K. However, if these conductions are intrinsic, i.e., due substantially to the polarization-discontinuity, they imply the existence of intrinsic screening in ferroelectric metal oxides that changes domains and size effects [14]. The necessity of this theory [14] was also shown through a conventional framework that showed the nano-domain formation in electrodeless ultrathin ferroelectric and its instability [16], which was used later by Bratkovsky-Levanyuk for nanodomain by fatigue [17].
To date, ohmic bipolar conduction at low applied voltage in initially high resistive ferroelectrics has been absent in conductions at domain boundaries and STO/LAO, indicating the extrinsicness such as defects and current injection by too large applied field [15]. Therefore, our presentation focuses on the properties of nominally stoichiometric clean surfaces of a high-purity BaTiO3 single crystals in ultrahigh vacuum as an idealized model of these conductions, especially, of a ferroelectric/insulator interface. The choice of BaTiO3 is because of a low coercive field to avoid high fields and a far lower defect concertation than Pb- and Bi-based ferroelectrics such as PbTiO3 and BiFeO3, which is essential for assuring intrinsicness. These surfaces exhibit ohmic bipolar conduction at low applied voltage with initially high resistivity and domain properties different from conventional views. Their implications will be discussed..
4. Yukio Watanabe, H. Nakahara(学部卒), S. Kaku(博士卒), D. Matsumoto(博士卒), S.-W Cheong, Natural domains of BaTiO3 in ultra-high vacuum, air & acid: properties & invariant domain-size proving intrinsic screening & a Review of polarization induced conduction  (招待講演) , International Meeting on Ferroelectricity (IMF14) , 2017.09, Conduction at SrTiO3/LaAlO3[1] is intensively studied. Before this, conduction at clean surface of fully oxygenated BaTiO3 in UHV (ultrahigh vacuum) was reported.[2] This verified also conduction at charged domain boundaries and dielectric/ferroelectric interfaces.[2] These conductances are too small for electronics but are fundamental for domains, because they screens depolarization field.[3]

Using nm-scale and macroscopic probes, we’ll clarify static and dynamic properties of natural domains of unpolished atomically flat surface of fully oxygenated stoichiometric BaTiO3 single crystal in UHV, air, and acid, which will be explained by DFT/GL calculations.

We show experimentally that the electrostatic domain patterns agree excellently with piezoelectric force response images (PFM) nearly complete screening of electric field from domains of atomically cleaned surface in UHV without extraneous screening.

Our experiments find conduction of both +PS surface and -PS surface. Our calculations show the location of each conduction is titanium of one unitcell deeper than top surface and the outermost oxygen, respectively.

The domain patterns in UHV, air and acid are found mutually very similar. In particular, we find a perfect agreement of domain patterns obtained by etching and PFM for the first time and invariance of domains of air in acid.

A critical finding is that the domain size/width in UHV, air, and acid was the same, despite 100-times difference of permittivity (screening efficiency) between UHV and acid.

These results verify intrinsic screening of depolarization field is inside ferroelectric, consistently with the evidence by conduction.[2] This screening explains the absence of natural vortex domains on free surface as well as properties of nano-ferroelectrics such as compulsory nano-domain.

1. Ohtomo-Hwang, Nature427(2004), 2. Watanabe et al, PRL86(2001), 3. Watanabe, PRB57(1998)..
5. Yukio Watanabe, Y. Urakami(修士卒), D. Matsumoto(博士卒), S. Kaku(博士卒), S.-W Cheong, G.A. Thomas, S. Miyauchi(修士卒), Novel Electrical Conduction of Oxide Insulators under examination of Defects & Injection & Relationship to theories of Ferroelectric Domain  (招待講演)                , Materials Research Society (MRS) 2014 Spring Meeting , 2014.04, As ferroelectric is miniaturized, it faces extreme conditions such as enormous depolarization field Ed and surface effects, of which intrinsic properties are unclarified. PS-field-effect (field effect by spontaneous polarization PS) may exist in such condition, relaxing the restrictions by Ed. However, it is usually regarded as extrinsic and is neglected in theories of nano-ferroelectrics and domains.
This is reasonable, because reported PS-field-effect may be due to (1) defects/impurities, especially, oxygen vacancies, and (2) electron/hole injection, which are examined in this talk. For example, resistance switching in Schottky [1-3], pn and tunnel [4] diodes using ferroelectrics including nano-scale ones [5] is often attributed to (1)(2) or PS. Similar switching in ordinary insulators (R-RAM), attributed to (1)(2), indicates that (1)(2) are unavoidable in 2-terminal structures. Indeed, the mechanism, PS [1,2] or injection/oxygen,[3] has been controversial until now. Here, rigorous treatment of current-voltage characteristics is crucial, and those assigned to PS [1] are precisely explained by injection.[6]
These difficulties (1)(2) exist also in PS-field-effect on the conductance perpendicular to PS, i.e., transconductance in 3-terminal. It is noted that the mechanisms (1)(2) exists in MOSFET, the most well-controlled clean system. Indeed, the mechanisms (1)(2) have been unavoidable since the proposals of PS-field-effect transconductance in 1957,[7] and transconductance modulation with retention mainly by PS were achieved after introduction of perovskite-oxide semiconductors.[8-10] For these reasons, this talk examines extrinsic effects (1)(2) including PS-induced modulation doping.
Nonetheless, it reports convincing evidences that self-PS-field-effect [11-14] exists in ferroelectric chemically same as that in air. Moreover, although imperfections cannot be reduced be below thermodynamic limit in O2 (samples contain impurities and defects of a few ppm), the analyses show that this effect is intrinsic and exists in ideal ferroelectrics without imperfections. These conclusions are drawn from transconductance in combination with nanoscopic measurements in UHV. To this end, the choice and preparation of samples are the most essential: BaTiO3 single crystals are used.
[1] T. Choi et al., Science324, 63(2009). [2] P. Blom et al., PRL73, 2107(1994). [3] Y.W. et al.,APL66, 28 (1995); Physica C235, 739(1994). [4] Y.W., PRB57, R5563(1998); JAP94, 7187(2003). [5] Y.W., APL72, 2415(1998). [6] Y.W., PRB81, 195210(2010). [7] C. Seager et al., Integrated Ferroelectr.6, 47 (1995). [8] Y.W.,  U.S. Patent 5418389(May, 1995). [9] Y.W. APL66, 1770(April,1995); Ext. Abst. SSDM’94, 784 (1994). [10] C. Ahn et al., Science269, 373 (July,1995). [11] M. Krômar and C. Fu, PRB 68, 115404(2003). [12] R. Cohen, Ferroelectr. 194, 323(1997). [13] Y.W. et al, Jpn. J. Appl. Phys. 36, 6162(1997); PRB 789 (1998). [14] Y.W. et al., PRL 86, 332(2001)..
6. Y. Watanabe, S. Kaku(博士卒), S. Miyauchi(修士卒), S.-W Cheong(Rutgers Univ), D. Matsumoto(博士卒) and Y. Urakami(修士卒), Statics and Dynamics of cc and ac Domains of Virtually Intrinsic Ferroelectric in Clean Limit (招待講演), International Meeting on Ferroelectricity (IMF13), 2013.09.
7. Y. Watanabe, D. Matsumoto(博士卒), S. Kaku(博士卒), and M. Arai, Properties of intrinsic ferroelectric surface in extreme clean limit: Giant 2D conduction on atomically clean surface of stoichiometric BaTiO3 in UHV for ferroelectric basics (招待講演) , 12th European Meeting on Ferroelectricity (EMF-2011), 2011.06.
8. Y. Watanabe Matsumoto(博士卒), S. Kaku(博士卒), Nanoscopic Domain Structure By Ultra-High Vacuum Multiple Probe Microscopy (招待講演) , ISAF-ECAPD 2010 (19th International Symposium on the Applications of Ferroelectrics,10th European Conference on the Applications of Polar Dielectrics), 2010.08.
9. Y. Watanabe Matsumoto(博士卒), S. Kaku(博士卒), Intrinsic surface carrier layer on ferroelectric surface macroscopic & nanoscopic study (招待講演 招聘) , Asia Pacific Center for Theoretical Physics The 3rd Workshop for Emergent Materials Research, 2010.07, test.
10. Y. Watanabe, Theoretical Proposal of Unidirectional Bulk Conduction under Trap Density Gradient and Description of Resistance Switching (招待講演), 7th AMF-AMEC-2010 (the 7th Asian Meeting on Ferroelectricity and the 7th Asian Meeting on ElectroCeramics, 2010.06.
11. S. Kaku(博士3年), K. Nakamura(学部)、D. Matsumoto(博士3年), and Y. Watanabe, UHV Properties of Ferroelectric Surface and Domain Revealed by Atomically Clean BaTiO3 Surface (準招待oral), Aspen conf. Advances in the Fundamental Physics of Ferroelectrics and Related Materials, 2010.01.
12. 渡部行男, 原子レベルで制御された強誘電体表面  (物理学会シンポ 招待), 日本物理学会, 2009.09.
13. Y. Watanabe, S. Kaku(博士3年), D. Matsumoto(博士3年), D. Nakahara(修士1年) and T. Minakuchi(修士1年), S. W. Cheong, and Masao Arai, Nanoscopic intrinsic properties of ferroelectric surface and domain revealed by atomically clean BaTiO3 surface in UHV  (招待講演  基礎セクションの巻頭講演), IMF 12-ISAF 2009 (12th International Meeting on Ferroelectricity and International Symposium on Application of Ferroelectricity, Joint meeting ), 2009.08.
14. Y. Watanabe, S. Kaku(博士2年), D. Matsumoto(博士2年),Y. Urakami(修士卒), S. Cheong , Investigation of Properties of Clean Surface of Ferroelectric in UHV (招待講演 基礎セッション巻頭講演), RCBJSF-9(The 9th Russian-CIS-Baltic-Japan Symposium on Ferroelectricity, 2008.06.
15. 渡部, はじめに (物理学会シンポ招待), 日本物理学会シンポ 強誘電体分域の測定法の新展開と新しい分域像(企画提案者), 2008.03.
16. Y. Watanabe,D. Matsumoto (博士1年), Y. Urakami (修士卒),  Bipolar Carrier (e-/h+) Layer on Clean Surface of Insulating BaTiO3 Crystal Intrinsic to Ferroelectrics (招待講演),  European Meeting on Ferroelectricity 11, 2007.09.
17. 渡部行男,  強誘電体表面の本質的自由電子ホール層 (招待講演),  日本物理学会, 2007.03.
18. Yukio Watanabe,  Status of Surface Electron Layer and Ferroelectric R-RAM (招待講演) ,  Asian Meeting on Ferroelectrics AMF-5, 2006.09.
19. Y. Watanabe, S. Kaku (修士2年), M. Yamato (修士2年) ,D. Matsumoto (修士2年),  Dynamics of Electrons and Holes in Ferroelectrics (招待講演),  The 6th Japan-Korea Conference on Ferroelectricity - JKC-FE06 -, 2006.08.
20. 渡部,   はじめに(物理学会シンポ招待),  日本物理学会シンポ:誘電体の電子ダイナミクス (企画者), 2006.03.
21. Y. Watanabe, Y. Urakami (修士2年), H. Yoshioka (修士卒), M.Yamato (修士1年),  Spontaneous Emergence of Free Carrier at Phase Transitions of Insulating BaTiO3 Single Crystals
(招待講演) ,  International Meeting on Ferroelectrics IMF-11, 2005.09.
22. 渡部,  強誘電体薄膜における界面の効果 (物理学会シンポ招待),  強誘電体薄膜および界面における新しい現象とその応用, 2005.09.
23. 渡部,  抵抗変化型不揮発メモリ(RRAM)の現状と展望 (招待講演),  日本学術振興会「物質科学とシステムデザイン —次世代エレクトロニクスの構築に向けてー」, 2004.02.
24. 渡部行男,  絶縁体中の電流?:電場や電流による誘電体の表面の意外な変化と応用 (招待講演),  茅コンファレンス, 2003.08.
25. 渡部行男,  遷移金属酸化物強誘電体:BaTiO3の表面電子系 (招待講演),  東北大金属材料研究所研究会, 2002.12.
26. 渡部 行男,  表面から見る強誘電体薄膜物性の規定と新物性 (物理学会シンポ招待),  日本物理学会 :遷移金属酸化物・強誘電体ナノ構造のサイズ効果とは何か (企画者) , 2001.09.
27. Y. Watanabe A. Masuda (修士卒) ,  NANO-SCALE THEORY OF FERROELECTRIC SURFACE PREDICTING SKIN-DEEP QUANTIZED 2D ELECTRON GAS (招待講演),  International Meeting on Ferroelectricity IMF-10, 2001.09.
28. Y. Watanabe, J. G. Bednorz, A. Bietsch, Ch. Gerber, and A. Beck,  Reversible conductance change and current driven insulator-metal transition in transition metal oxide dielectrics (招待講演),  The 2nd International Workshop on Novel Quantum Phenomena in Transition Metal Oxides, 2001.08.
29. 渡部行男,  遷移金属酸化物強誘電体の接合界面(pn接合等) (招待講演),  遷移金属酸化物の化学 , 2001.06.
30. 渡部行男,  微小強誘電体の応用における原理的問題と現状 (物理学会シンポ招待),  日本物理学会シンポ “誘電体物理の新展開と21世紀への課題―PbZrO3反強誘電性発見50周年―”, 2000.03.
31. Y. Watanabe,  FERROELECTRIC SELF-FIELD EFFECT : IMPLICATIONS FOR SIZE EFFECT AND MEMORY DEVICE (招待講演),  International Symposium on Integrated Ferroelectrics, 1999.03.
32. 渡部行男,  強誘電体薄膜の物理的基礎:全ペロブスカイト強誘電体半導体構造の物性と応用 (招待講演),  第3回九州薄膜表面研究会, 1998.10.
33. 渡部行男,  酸化物ペロブスカイト及びその周辺物質による強誘電体ヘテロ構造 (招待講演),  電子セラミック・プロセス研究会特別講演会, 1997.01.
34. 渡部行男,  酸化物・金属・半導体界面の評価:ペロブスカイトヘテロ構造の展開 (招待講演),  超伝導工学研究所調査委員会, 1996.01.
35. 渡部行男,  全ペロブスカイト強誘電体/半導体構造によるメモリー性FET等 (招待講演),  第14回電気学会低温エレクトロニクス調査専門委員会, 1995.04.
36. 渡部行男,  銅酸化物超伝導体の中赤外分光 (招待講演) ,  応用磁気学会超伝導マグネティクス研究会, 1992.10.
特許出願・取得
特許出願件数  61件
特許登録件数  12件
その他の優れた研究業績
1990.01, 光磁気ディスクの実用化 大規模生産 (研究段階の主担当者)
’.
1987.01, ピッチ系カーボンファイバーの高強度化の原理を提案し、大規模生産に用いられた.
1988.05, (米国特許(成立)) Magnetooptic medium with oxide thin layer 吉富、小林、佐々木、渡部.
1995.05, (米国特許(成立)) Field effect transistor with perovskite oxide channel 渡部
(殆ど全てのぺロブスカイト酸化物をチャンネルとして用いる強誘電体FETの基本特許).
2001.01, (日本国特許成立)  電界効果素子用積層薄膜および該積層薄膜を用いた電界効果トランジスタ 渡部
(殆ど全てのぺロブスカイト酸化物をチャンネルとして用いる強誘電体FETの基本特許).
1995.06, (米国特許(成立)) A layer by layer vapor deposition method for forming a high-Tc superconductor thin film device 渡部.
学会活動
所属学会名
日本物理学会
American Physical Society
American Geophysical Union
学協会役員等への就任
2017.04~2018.03, 日本物理学会九州支部, 支部長.
2004.04~2008.03, 日本学術振興会, プログラムオフィサー.
2007.04~2011.03, 日本物理学会, 代議員.
2002.10~2003.09, 日本物理学会, 世話人.
2009.10~2011.07, 日本物理学会九州支部, 幹事.
2002.10~2003.09, 日本物理学会九州支部, 幹事.
学会大会・会議・シンポジウム等における役割
2019.07.14~2019.07.19, 14th European Meeting on Ferroelectricity (2019 IEEE ISAF-ICE-EMF-IWPM-PFM Joint Conference内), 座長(Chairmanship).
2014.04.21~2013.04.25, MRS (Materials Research Society ) 2014 Spring Meeting, 座長(Chairmanship).
2013.09.01~2013.09.06, International Meeting on Ferroelectricity (IMF13), 座長(Chairmanship).
2011.06.26~2011.07.01, 12th European Meeting on Ferroelectricity (EMF-2011), 座長(Chairmanship).
2010.08.09~2010.08.12, ISAF-ECAPD 2010 (19th International Symposium on the Applications of Ferroelectrics,10th European Conference on the Applications of Polar Dielectrics), 座長(Chairmanship).
2010.07.05~2010.07.07, The 3rd Workshop for Emergent Materials Research, 座長(Chairmanship).
2010.06.28~2010.07.01, 7th AMF-AMEC-2010 (the 7th Asian Meeting on Ferroelectricity and the 7th Asian Meeting on ElectroCeramics), 座長(Chairmanship).
2009.08.23~2009.08.27, IMF 12-ISAF 2009 (Joint meeting of 12th International Meeting on Ferroelectricity and International Symposium on Application of Ferroelectricity), 座長(Chairmanship).
2009.09.25~2009.09.28, 日本物理学会 シンポジウム, 座長(Chairmanship).
2008.08.06~2008.08.10, The 7th Korea-Japan Conference on Ferroelectricity (KJCFE-07) , 座長(Chairmanship).
2008.03.22~2008.03.26, 日本物理学会 シンポジウム, 座長(Chairmanship).
2006.09.01~2006.09.10, The 6th Japan-Korea Symposium on Ferroelectrics , 座長(Chairmanship).
2006.05.01~2006.05.30, 8th Russia/CIS/Baltic/Japan Symposium on Ferroelectricity, 座長(Chairmanship).
2006.03.01~2006.03.31, 物理学会シンポジウム, 座長(Chairmanship).
2004.08.01~2004.08.30, The 5th Korea-Japan Symposium on Ferroelectrics, 座長(Chairmanship).
2003.09.01~2003.09.30, 物理学会 シンポジウム, 座長(Chairmanship).
2001.09.01~2001.09.30, 物理学会 シンポジウム, 座長(Chairmanship).
2001.09.01~2001.09.01, 物理学会 シンポジウム: 遷移金属酸化物・強誘電体ナノ構造のサイズ効果とは何か, シンポジウム企画者組織者.
2000.03.01~2000.03.31, 物理学会 シンポジウム, 座長(Chairmanship).
2014.04.20~2014.04.25, Materials Research Society (MRS) 2014 Spring Meeting, 座長.
2014.04.20~2014.04.25, Materials Research Society (MRS) 2014 Spring Meeting, シンポジウムJ 申請の主な講演者, シンポジウム概要中の主講演者.
2010.08.03~2010.08.06, The 7th Korea-Japan Conference on Ferroelectricity (KJCFE-07) , 組織委員.
2010.06.21~2010.06.25, RCBJSF-9(The 9th Russian-CIS-Baltic-Japan Symposium on Ferroelectricity), 組織委員.
2008.08.06~2008.08.10, The 7th Korea-Japan Conference on Ferroelectricity (KJCFE-07) , 組織委員.
2008.03.01~2008.03.31, 強誘電体分域の測定法の新展開と新しい分域像, 企画提案者.
2006.03.01~2006.03.31, 物理学会 シンポジウム, 提案企画者.
2004.08.01~2004.08.31, The 7th Korea-Japan Conference on Ferroelectricity (KJCFE-05) , プログラム委員.
2004.03.01~2004.03.31, 日本物理学会 年会, 実行委員.
2001.09.01~2001.09.30, 物理学会シンポジウム, 提案企画者.
学会誌・雑誌・著書の編集への参加状況
2006.04~2007.03, 固体物理, 国内, 誌友.
2002.10, Integrated Ferroelectrics, 国際, 編集委員.
1995.08, Applied Physics Letters, 国際, 登録査読員.
2004.09, Physical Review, 国際, 登録査読員.
2004.08, Journal of Applied Physics, 国際, 登録査読員.
学術論文等の審査
年度 外国語雑誌査読論文数 日本語雑誌査読論文数 国際会議録査読論文数 国内会議録査読論文数 合計
2018年度    
2017年度    
2016年度    
2015年度    
2014年度    
2013年度    
2012年度    
2011年度    
2010年度 11      11 
2009年度 10      10 
2008年度    
2007年度 10      10 
2006年度 10      11 
2005年度      
2004年度      
2003年度
2002年度
2001年度
2000年度
1999年度
1998年度
1997年度
1996年度
その他の研究活動
海外渡航状況, 海外での教育研究歴
SwissTech Convention Center, Lausanne, Switzerland, 2019.07~2019.07.
Dr. Bednorz (IBM Zurich lab), Switzerland, 2019.07~2019.07.
Univ Southern Florida, UnitedStatesofAmerica, 2019.01~2019.01.
Carnegie Institute, UnitedStatesofAmerica, 2018.01~2018.01.
New Jersey Inst. Tech, UnitedStatesofAmerica, 2017.09~2017.09.
Princeton U., UnitedStatesofAmerica, 2017.09~2017.09.
International Meeting on Ferroelectricity IMF-14 , UnitedStatesofAmerica, 2017.09~2017.09.
Institute of High Performance Computing, Singapore, 2015.06~2015.06.
MRS 2014, UnitedStatesofAmerica, 2014.04~2014.04.
International Meeting on Ferroelectricity IMF-13, Poland, 2013.09~2013.09.
T U Wien, Austria, 2013.09~2013.09.
Princeton U. , UnitedStatesofAmerica, 2012.10~2012.10.
Californina Institute of Technology (Caltech), UnitedStatesofAmerica, 2012.10~2012.10.
Fundamental Physics of Ferroelectrics 2012, UnitedStatesofAmerica, 2012.01~2012.02.
European Meeting on Ferroelectricity 12 (EMF2012), France, 2011.06~2011.07.
ETH スイス連邦工科大学, Switzerland, 2010.08~2010.08.
Asia Pacific Center for Theoretical Physics , SouthKorea, 2010.07~2010.07.
IBM Zurich Lab. (host Dr. Bednorz), Univ. Nijemegen (host Prof. Janssen), Switzerland, Netherlands, 2010.08~2010.08.
Aspen conf. , UnitedStatesofAmerica, 2010.02~2010.02.
International Meeting on Ferroelectricity IMF-12 2009, China, 2009.08~2009.08.
Fundamental Physics of Ferroelectrics 2009, UnitedStatesofAmerica, 2009.02~2009.02.
American Physical Society March Meeting , UnitedStatesofAmerica, 2009.03~2009.03.
Japan-Korea Symposium on Ferroelectricity, Korea, 2008.08~2008.08.
RCBJSF-9(The 9th Russian-CIS-Baltic-Japan Symposium on Ferroelectricity), Lithuania, Vilnius, 2008.06~2008.06.
American Physical Society March Meeting , UnitedStatesofAmerica, 2008.03~2008.03.
Princeton U. (host Prof. Tsui), Rutgers U., UnitedStatesofAmerica, UnitedStatesofAmerica, 2008.03~2008.03.
IBM Zurich Lab. (host Dr. Bednorz), Univ Augusburg (Prof. Mannhart), Switzerland, Germany, 2008.02~2008.02.
IBM Zurich Lab. (host:Dr. Bednorz), Switzerland, 2007.09~2007.09.
European Meeting on Ferroelectricity 11, Slovenia, 2007.09~2006.09.
International Meeting on Ferroelectricity 11, Brazil, 2005.09~2005.11.
APS, UnitedStatesofAmerica, 2005.03~2005.03.
Japan-Korea Symposium on Ferroelectricity, Korea, 2004.08~2004.08.
European Meeting on Ferroelectricity 11, UnitedKingdom, 2003.08~2003.08.
APS, Princeton U., Rutgers U., UnitedStatesofAmerica, 2003.02~2003.03.
International Meeting on Ferroelectricity 10, Spain, 2001.09~2001.09.
IBM Zurich研究所  (Dr. Bedrnoz (87年ノーベル物理学賞)との共同研究), Switzerland, 2000.03~2000.06.
Asian Meeting on Ferroelectricity AMF-3, Hong Kong , 1999.12~1999.12.
Magnetism and Magnetic Materials ‘99, UnitedStatesofAmerica, 1999.11~1999.11.
Bell Lab., Princeton University (九州産業局支援によるベル研での共同研究), UnitedStatesofAmerica, 1998.07~1998.10.
International Meeting on Ferroelectricity 9, Korea, 1997.08~1997.08.
Gordon conferrence, Princeton Univ., UnitedStatesofAmerica, 1996.07~1996.07.
Princeton Univ., Yale Univ. , UnitedStatesofAmerica, UnitedStatesofAmerica, 1994.07~1994.07.
Bell Lab., Bellcore Lab., New York State Univ. at Bufflo, UnitedStatesofAmerica, 1994.07~1994.07.
IBM Zurich 研究所 (host:Dr. Bednorz), Switzerland, 1994.07~1994.07.
M2S-HTSC IV '94, France, 1994.07~1994.07.
ECD , New York State Univ. at Bufflo, Princeton Univ., UnitedStatesofAmerica, 1992.07~1992.07.
Symmetrix Inc., Applied Superconductivity Conferrence '92, Univ.California San Diego , UnitedStatesofAmerica, 1992.07~1992.07.
MRS, Advanced Materials Inc., Princeton Univ., American Superconductors, UnitedStatesofAmerica, 1990.11~1990.12.
Princeton University (Tsui教授('98 ノーベル物理学賞)に2年間師事 社費留学), UnitedStatesofAmerica, 1987.08~1989.09.
University of Alaska, UnitedStatesofAmerica, 1985.12~1985.12.
Max Planck Institut fuer Astrophysik, GeophysiKalische Institut (Gauss Institut)(学部4年時), Germany, 1980.02~1980.03.
外国人研究者等の受入れ状況
2013.11~2013.11, 2週間未満, University of Nijimegen, Russia, 量子物性科学I講座.
2010.06~2010.06, 2週間未満, University of Nebraska, Russia, 量子物性科学I講座.
2009.09~2009.09, 2週間未満, IBM Zurich lab, Germany, 量子物性科学I講座.
2006.09~2006.09, 2週間未満, University of Nijmegen, Netherlands, 量子物性科学I講座 及び FRプロジェクト.
2006.09~2006.09, 2週間未満, University of Cambridge, Germany, 量子物性科学I講座 及び FRプロジェクト.
2006.08~2006.08, 2週間未満, Princeton University, UnitedStatesofAmerica, 量子物性科学I講座.
2004.10~2004.10, 2週間未満, IBM, Germany, 日本学術振興 及び 量子物性科学I講座.
受賞
Cornig賞, Cornig Japan, 1996.10.
研究資金
科学研究費補助金の採択状況(文部科学省、日本学術振興会)
2014年度~2017年度, 挑戦的萌芽研究, 代表, 金属酸化物からのトンネル電子による、結晶性酸化物ヘテロ接合の形成.
2007年度~2008年度, 基盤研究(B), 代表, 原子レベルで平坦な強誘電体の清浄表面の形成とその伝導層の物性解明.
2004年度~2006年度, 基盤研究(B), 代表, 強誘電体分域境界に生じる自発分極と結合した自由電子系の確定と解明.
2005年度~2006年度, 萌芽研究, 代表, 絶縁体金属転移の電界制御を利用した量子細線・量子ドットの作製とその物性研究.
2002年度~2002年度, 特定領域研究(A)特定領域研究(B), 代表, 遷移金属酸化物強誘電体中の電荷秩序と自由電子の結合による物性の解明.
2001年度~2002年度, 基盤研究(C), 代表, 強誘電体清浄表面の自発的電子層による伝導の同定.
2000年度~2003年度, 特定領域研究(A)特定領域研究(B), 分担, 強誘電体の電気特性の発現機構の基礎的解明 (計画班).
1997年度~1999年度, 一般研究(B), 分担, 電磁妨害波測定用実験室の高性能化に関する研究.
1996年度~1998年度, 一般研究(B), 代表, 強誘電体/半導体結晶整合ヘテロ構造の単結晶性膜作製と電子機能性開拓.
科学研究費補助金の採択状況(文部科学省、日本学術振興会以外)
1998年度~1998年度, 九州産業局, 代表, 米国長期共同研究 .
日本学術振興会への採択状況(科学研究費補助金以外)
2008年度~2008年度, 二国間交流, 分担, 二国間交流事業
事業名:韓国KOSEFとの共同研究・セミナー 代表者:兵庫県立大学・大学院工学研究科 教授・清水 勝
セミナー名:第7回韓日強誘電体会議 セミナー開催期間:8/7-8/9.
2002年度~2002年度, 国際学会等派遣事業, 代表, 物理分野.
競争的資金(受託研究を含む)の採択状況
2006年度~2007年度, カシオ科学技術財団, 代表, 強誘電体薄膜の抵抗記憶効果の原理解明及びそれに基づく多値不揮発メモリー素子の開発.
2001年度~2002年度, 材料科学研究助成, 代表, チタン酸化物誘電体単結晶中の電子伝導を用いた新光電子機能の開拓.
2000年度~2001年度, 旭ガラス財団, 代表, 強誘電性体自由極表面上の電子格子結合系の基礎物性及びその光電子特性の開拓.
2000年度~2001年度, 泉科学技術振興財団, 代表, 原子層表面処理と分域工学を施したBaTiO3単結晶による冷電子源.
1999年度~1999年度, 池谷科学技術振興財団, 代表, 強誘電体セラミックを用いた高耐性pnダイオード及び光ダイオードの開発.
1998年度~1999年度, 矢崎科学技術振興記念財団, 代表, 強誘電体薄膜の極薄膜化極限の物性の理論予測.
1997年度~1998年度, 村田学術振興財団研究助成, 代表, ビーム状スパッター源を用いた低圧成膜による極平坦な強誘電体単結晶薄膜の低温成膜法.
1997年度~1997年度, 小笠原科学振興財団, 代表, 超高真空オゾン処理による金属/エピタキシャル強誘電体界面を用いたぺロブスカイト型強誘電体の電気特性改善と表面電子構造の解明.
1997年度~1997年度, C&C財団, 代表, 強誘電体国際会議出席 海外渡航.
1996年度~1997年度, 住友財団 基礎科学研究助成, 代表, ぺロブスカイト酸化物/半導体ヘテロ単結晶構造の物性探索.
共同研究、受託研究(競争的資金を除く)の受入状況
2007.04~2008.03, 代表, 超高真空中の清浄な表面をもつ強誘電体の分域構造の研究 .
2006.04~2007.03, 代表, 誘電体、光物性、半導体分野に関する学術動向の調査・研究 .
2005.04~2006.03, 代表, 誘電体、光物性、半導体分野に関する学術動向の調査・研究.
2004.04~2005.03, 代表, 誘電体、光物性、半導体分野に関する学術動向の調査・研究.
寄附金の受入状況
1996年度, 渡部行男
(Corning Grant賞受賞による寄付),    Investigation of nano-scale electrical properties of single-crystal ferroelectric film for forecasting their miniaturization limit.
学内資金・基金等への採択状況
1996年度~1998年度, 九州工業大学 COE形成費, 代表, 高結晶誘電体膜とそのヘテロ構造のナノ物性・光電子機能の開拓  (酸化物エレクトロニクスの研究基盤構築に向けて).
2000年度~2000年度, 九州工業大学開学75周年記念事業, 代表, 誘電体の電気伝導の海外共同研究.

九大関連コンテンツ

pure2017年10月2日から、「九州大学研究者情報」を補完するデータベースとして、Elsevier社の「Pure」による研究業績の公開を開始しました。
 
 
九州大学知的財産本部「九州大学Seeds集」