2001 Fiscal Year Annual Research Report

半導体超構造における電子のスピンコヒーレンスとその制御

Research Project

Project/Area Number	12305001
Research Institution	Tohoku University
Principal Investigator	大野英男東北大学, 電気通信研究所, 教授 (00152215)
Co-Investigator(Kenkyū-buntansha)	松倉文礼東北大学, 電気通信研究所, 助手 (50261574) 大野裕三東北大学, 電気通信研究所, 助教授 (00282012)
Keywords	スピンコヒーレンス / 磁性半導体 / キャリアスピン / 核スピン / キャリア誘起強磁性 / スピン注入 / 核スピン共鳴 / 強磁性体
Research Abstract	本研究では従来の(非磁性)半導体量子構造と、新たに創生されつつある強磁性半導体との融合構造に基礎を置き、そこにおける(1)電子のスピンコヒーレンスの顕示と外場による制御、(2)核スピンや磁性イオンとの相互作用の解明と制御、さらに(3)スピンに依存する電子・光物性を活用した新しいデバイスのプロトライプの作製を目的として研究を進めている。本年度の主な成果は以下の通りである。 (1)強磁性/非磁性半導体トンネル接合におけるスピン偏極電子注入 p型強磁性半導体(Ga,Mn)Asとn^+-GaAsからなるスピンエサキダイオードを作製し、(Ga,Mn)Asの価電子帯から非磁性GaAsの伝導帯へのバンド間トンネルを用いてスピン偏極電子の注入を行った。スピンエサキダイオードのn^+-GaAs側に形成した非磁性半導体発光ダイオードの偏光を測定したところ、明瞭なヒステリシスが観測され、ゼロ磁場でのスピン偏極電子の電流注入を世界ではじめて確認した。偏光度の大きさは従来のスピン偏極正孔注入の5倍であった。 (2)核スピンとの相互作用の解明と制御電子スピンのコヒーレンスが非常に長い(110)面GaAs/AlGaAs量子井戸構造に注目し、電子スピンと核スピンの相互作用ダイナミクスを時間分解ファラデー回転測定によって調べた結果、高い核スピン分極率と共鳴現象を観測し、半導体量子井戸構造において全光核磁気共鳴が可能であることがわかった。 (3)室温強磁性ハーフメタルCrSbの開発低温成長時における非平衡表面層を利用することによって、自然界には存在しない閃亜鉛鉱型CrSbをGaAs上にエピタキシャル成長させることに成功し、それが室温で強磁性体であることを明らかにした。

Research Products
(24 results)

All Other

All Publications (24 results)

[Publications] H.Ohno: "Semiconductor spin electronics"JSAP International. No.5. 4-13 (2002)
[Publications] T.Tsuruoka: "Microscopic identification of dopant atoms in Mn-doped GaAs layer"Solid State Communications. Vol.121. 79-82 (2002)
[Publications] M.Kohda: "A Spin Esaki Diode"Jpn. J. Appl. Phys. Vol.40, No.12. L1-L3 (2001)
[Publications] Y.Nagai: "Spin polarization dependent far-infrared absorption in Ga_<1-x>Mn_XAs"Jpn. J. Appl. Phys. Vol.40, No.11. 6231-6234 (2001)
[Publications] G.Salis: "Origin of enhanced dynamic nuclear polarization and all-optical nuclear magnetic resonance in GaAs quantum wells"Physical Review B. Vol.64. 195304(1)-195304(10) (2001)
[Publications] J.H.Zhao: "Room-temperature ferromagnetism in zincblende CrSb grown by molecular beam epitaxy"Applied Physics Letters. Vol.79, No.22. 2776-2779 (2001)
[Publications] K.Takamura: "Growth and properties of (Ga,Mn)As films with high Mn concentration"Journal of Applied Physics. Vol.89, No.11. 7024-7026 (2001)
[Publications] H.Ohno: "Spin-Dependent Properties of Ferromagnetic/Nonmagnetic GaAs Heterostructures"Material Science and Engineering B. Vol.84. 70-74 (2001)
[Publications] H.Kubota: "Magnetoresistance and Dipole Shift of Ultrasmall Magnetic Tunnel Junctions Characterized by Conducting Atomic Force Microscopy"Japanese Journal of Applied Physics. 41(in press). (2002)
[Publications] Eiji Nakashio: "Longitudinal bias method using a long distance exchange coupling field in TMR junction"Journal of Applied Physics. 89. 7356-7358 (2001)
[Publications] Eiji Nakashio: "Flux guide type tunnel-value head for tape storage applications"IEEE Transaction on Magnetics. (in press).
[Publications] T.Fukumura: "Magnetic domain structure of a ferromagnetic semiconductor (Ga, Mn)As observed with scanning probe microscopes"Physica E. Volume 10, Issues 1-3. 135-138 (2001)
[Publications] T.Omiya: "Magnetotransport properties of (Ga, Mn)As grown on GaAs(411) A substrates"Physica E. Volume 10, Issues 1-3. 206-209 (2001)
[Publications] S.Ueda: "Magnetic circular dichroism in Mn 2p core absorption of Ga_<1-X>Mn_xAs"Physica E. Volume 10, Issues 1-3. 210-214 (2001)
[Publications] D.Chiba: "Properties of (Ga, Mn)As/(Al, Ga)As/(Ga, Mn)As magnetic trilayer structures"Physica E. Volume 10, Issues 1-3. 278-282 (2001)
[Publications] I.Arata: "Temperature dependence of electroluminescence and I-V characteristics of ferromagnetic/non-magnetic semiconductor pn junctions"Physica E. Volume 10, Issues 1-3. 288-291 (2001)
[Publications] Y.Ohno: "Electrical spin injection in ferromagnetic/nonmagnetic semiconductor heterostructures"Physica E. Volume 10, Issues 1-3. 489-492 (2001)
[Publications] T.Adachi: "Spin relaxation in n-modulation doped GaAs/AlGaAs (110) quantum wells"Physica E. Volume 10, Issues 1-3. 36-39 (2001)
[Publications] G.Salis: "Optical Manipulation of Nuclear Spin by a Two-Dimensional Electron Gas"Physical Review Letters. Volume 86, No. 12. 2677-2680 (2001)
[Publications] T.Dietl: "Hole-mediated ferromagnetism in tetrahedrally coordinated semiconductors"Physical Review B. Volume 63. 195205-195215 (2001)
[Publications] H.Ohno: "A ferromagnetic III-V semiconductor : (Ga, Mn)As"Solid State Communications. Vol.117, Issues 3. 179-186 (2001)
[Publications] H.Ofuchi: "Fluorescence extendedx-ray absorption fine structure study on local structures around Mn-atoms in thin (In, Mn)As layer and (In, Mn)As quantum dots"Journal of Applied Physics. Volume 89, Issues 1. 66-70 (2001)
[Publications] T.Dietl: "Ferromagnetism in III-V and II-VI semiconductor structures"Physica E. Volume 9, Issues 1. 185-193 (2001)
[Publications] F.Matsukura: "Handbook of Magnetic Materials"III-V Ferromagnetic Semiconductor. 42 (2002)

2001 Fiscal Year Annual Research Report

半導体超構造における電子のスピンコヒーレンスとその制御

Principal Investigator

大野 英男 東北大学, 電気通信研究所, 教授 (00152215)

Research Products

[Publications] H.Ohno: "Semiconductor spin electronics"JSAP International. No.5. 4-13 (2002)

[Publications] T.Tsuruoka: "Microscopic identification of dopant atoms in Mn-doped GaAs layer"Solid State Communications. Vol.121. 79-82 (2002)

[Publications] M.Kohda: "A Spin Esaki Diode"Jpn. J. Appl. Phys. Vol.40, No.12. L1-L3 (2001)

[Publications] Y.Nagai: "Spin polarization dependent far-infrared absorption in Ga_<1-x>Mn_XAs"Jpn. J. Appl. Phys. Vol.40, No.11. 6231-6234 (2001)

[Publications] G.Salis: "Origin of enhanced dynamic nuclear polarization and all-optical nuclear magnetic resonance in GaAs quantum wells"Physical Review B. Vol.64. 195304(1)-195304(10) (2001)

[Publications] J.H.Zhao: "Room-temperature ferromagnetism in zincblende CrSb grown by molecular beam epitaxy"Applied Physics Letters. Vol.79, No.22. 2776-2779 (2001)

[Publications] K.Takamura: "Growth and properties of (Ga,Mn)As films with high Mn concentration"Journal of Applied Physics. Vol.89, No.11. 7024-7026 (2001)

[Publications] H.Ohno: "Spin-Dependent Properties of Ferromagnetic/Nonmagnetic GaAs Heterostructures"Material Science and Engineering B. Vol.84. 70-74 (2001)

[Publications] H.Kubota: "Magnetoresistance and Dipole Shift of Ultrasmall Magnetic Tunnel Junctions Characterized by Conducting Atomic Force Microscopy"Japanese Journal of Applied Physics. 41(in press). (2002)

[Publications] Eiji Nakashio: "Longitudinal bias method using a long distance exchange coupling field in TMR junction"Journal of Applied Physics. 89. 7356-7358 (2001)

[Publications] Eiji Nakashio: "Flux guide type tunnel-value head for tape storage applications"IEEE Transaction on Magnetics. (in press).

[Publications] T.Fukumura: "Magnetic domain structure of a ferromagnetic semiconductor (Ga, Mn)As observed with scanning probe microscopes"Physica E. Volume 10, Issues 1-3. 135-138 (2001)

[Publications] T.Omiya: "Magnetotransport properties of (Ga, Mn)As grown on GaAs(411) A substrates"Physica E. Volume 10, Issues 1-3. 206-209 (2001)

[Publications] S.Ueda: "Magnetic circular dichroism in Mn 2p core absorption of Ga_<1-X>Mn_xAs"Physica E. Volume 10, Issues 1-3. 210-214 (2001)

[Publications] D.Chiba: "Properties of (Ga, Mn)As/(Al, Ga)As/(Ga, Mn)As magnetic trilayer structures"Physica E. Volume 10, Issues 1-3. 278-282 (2001)

[Publications] I.Arata: "Temperature dependence of electroluminescence and I-V characteristics of ferromagnetic/non-magnetic semiconductor pn junctions"Physica E. Volume 10, Issues 1-3. 288-291 (2001)

[Publications] Y.Ohno: "Electrical spin injection in ferromagnetic/nonmagnetic semiconductor heterostructures"Physica E. Volume 10, Issues 1-3. 489-492 (2001)

[Publications] T.Adachi: "Spin relaxation in n-modulation doped GaAs/AlGaAs (110) quantum wells"Physica E. Volume 10, Issues 1-3. 36-39 (2001)

[Publications] G.Salis: "Optical Manipulation of Nuclear Spin by a Two-Dimensional Electron Gas"Physical Review Letters. Volume 86, No. 12. 2677-2680 (2001)

[Publications] T.Dietl: "Hole-mediated ferromagnetism in tetrahedrally coordinated semiconductors"Physical Review B. Volume 63. 195205-195215 (2001)

[Publications] H.Ohno: "A ferromagnetic III-V semiconductor : (Ga, Mn)As"Solid State Communications. Vol.117, Issues 3. 179-186 (2001)

[Publications] H.Ofuchi: "Fluorescence extendedx-ray absorption fine structure study on local structures around Mn-atoms in thin (In, Mn)As layer and (In, Mn)As quantum dots"Journal of Applied Physics. Volume 89, Issues 1. 66-70 (2001)

[Publications] T.Dietl: "Ferromagnetism in III-V and II-VI semiconductor structures"Physica E. Volume 9, Issues 1. 185-193 (2001)

[Publications] F.Matsukura: "Handbook of Magnetic Materials"III-V Ferromagnetic Semiconductor. 42 (2002)

大野英男東北大学, 電気通信研究所, 教授 (00152215)