Publications >>Japanese Since 7. 2007 Full list of publications (boldface: important publications) On-chip transfer of ultrashort graphene plasmon wavepackets using terahertz electronics K. Yoshioka, G. Bernard, T. Wakamura, M. Hashisaka, K. Sasaki, S. Sasaki, K. Watanabe, T. Taniguchi, and N. Kumada arXiv:2311.02821 Gate-tunable giant superconducting nonreciprocal transport in few-layer Td-MoTe2 T. Wakamura, M. Hashisaka, S. Hoshino, M. Bard, S. Okazaki, T. Sasagawa, T. Taniguchi, K. Watanabe, K. Muraki, and N. Kumada Phys. Rev. Research 6, 013132 (2024). Emission and coherent control of Levitons in graphene A. Assouline, L. Pugliese, H. Chakraborti, S. Lee, L. Bernabeu, M. Jo, K. Watanabe, T. Taniguchi, D. C. Glattli, N. Kumada, H.-S. Sim, F. D. Parmentier, and P. Roulleau Science 382, 1260 (2023). Coherent-Incoherent Crossover of Charge and Neutral Mode Transport as Evidence for the Disorder-Dominated Fractional Edge Phase M. Hashisaka, T. Ito, T. Akiho, S. Sasaki, N. Kumada, N. Shibata, and K. Muraki Phys. Rev. X 13, 031024 (2023). Fast time-domain current measurement for quantum dot charge sensing using a homemade cryogenic transimpedance amplifier H. Bohuslavskyi, M. Hashisaka, T. Shimizu, T. Akiho, K. Muraki, and N. Kumada Appl. Phys. Lett. 121, 184003 (2022). Time-resolved measurement of ambipolar edge magnetoplasmon transport in InAs/InGaSb composite quantum wells H. Kamata, H. Irie, N. Kumada, and K. Muraki Phys. Rev. Research 4, 033214 (2022). Scaling behavior of electron decoherence in a graphene Mach-Zehnder interferometer M. Jo, J. M. Lee, A. Assouline, P. Brasseur, K. Watanabe, T. Taniguchi, P. Roche, D. C. Glattli, N. Kumada, F. D. Parmentier, H. -S. Sim & P. Roulleau Nature Commun. 13, 5473 (2022). Ultrafast intrinsic optical-to-electrical conversion dynamics in graphene photodetector Katsumasa Yoshioka, Taro Wakamura, Masayuki Hashisaka, Kenji Watanabe, Takashi Taniguchi, and Norio Kumada Nature Photonics 16, 718 (2022). Homemade-HEMT-based transimpedance amplifier for high-resolution shot-noise measurements Takase Shimizu, Masayuki Hashisaka, Heorhii Bohuslavskyi, Takafumi Akiho, Norio Kumada, Shingo Katsumoto, and Koji Muraki Rev. Sci. Inst. 92, 124712 (2021). Excitonic nature of magnons in a quantum Hall ferromagnet A. Assouline, M. Jo, P. Brasseur, K. Watanabe, T. Taniguchi, Th. Jolicoeur, D. C. Glattli, N. Kumada, P. Roche, F. D. Parmentier, and P. Roulleau Nature Phys. 17, 1369 (2021). Quantum Hall Valley Splitters and a Tunable Mach-Zehnder Interferometer in Graphene M. Jo, P. Brasseur, A. Assouline, G. Fleury, H.-S. Sim, K. Watanabe, T. Taniguchi, W. Dumnernpanich, P. Roche, D. C. Glattli, N. Kumada, F. D. Parmentier, and P. Roulleau Phys. Rev. Lett. 126, 146803 (2021). (Featured in Physics, Editors' suggestion) On-chip coherent frequency-domain THz spectroscopy for electrical transport Katsumasa Yoshioka, Norio Kumada, Koji Muraki, Masayuki Hashisaka Appl. Phys. Lett. 117, 161103 (2020). (editor's pick) Suppression of gate screening on edge magnetoplasmons by highly resistive ZnO gate N. Kumada, N.-H. Tu, K.-i. Sasaki, T. Ota, M. Hashisaka, S. Sasaki, K. Onomitsu, and K. Muraki Phys. Rev. B 101, 205205 (2020). Active spatial control of terahertz graphene plasmons Ngoc Han Tu, Katsumasa Yoshioka, Satoshi Sasaki, Makoto Takamura, Koji Muraki, and Norio Kumada Commun. Mater. 1, 7 (2020). Plasmon Control Driven by Spatial Carrier Density Modulation in Graphene Makoto Takamura, Norio Kumada, Shengnan Wang, Kazuhide Kumakura, and Yoshitaka Taniyasu ACS Photon. 6, 947 (2019). Plasmon confinement by carrier density modulation in graphene Ngoc Han Tu, Makoto Takamura, Yui Ogawa, Satoru Suzuki, and Norio Kumada Jpn. J. Appl. Phys. 57 110307 (2018). Coupling between Quantum Hall Edge Channels on Opposite Sides of a Hall Bar N. H. Tu, M. Hashisaka, T. Ota, Y. Sekine, K. Muraki, T. Fujisawa, and N. Kumada Solid State Commun. 283, 32 (2018). Charge fractionalization in artificial Tomonaga-Luttinger liquids with controlled interaction strength Paul Brasseur, Ngoc Han Tu, Yoshiaki Sekine, Koji Muraki, Masayuki Hashisaka, Toshimasa Fujisawa, and Norio Kumada Phys. Rev. B 96, 081101(R) (2017). Quantum Hall effect in epitaxial graphene with permanent magnets F. D. Parmentier, T. Cazimajou, Y. Sekine, H. Hibino, H. Irie, D. C. Glattli, N. Kumada, and P. Roulleau Scientific Reports 6, 38393 (2016). Andreev reflection and bound state formation in a ballistic two-dimensional electron gas probed by a quantum point contact Hiroshi Irie, Clemens Todt, Norio Kumada, Yuichi Harada, Hiroki Sugiyama, Tatsushi Akazaki, and Koji Muraki Phys. Rev. B 94, 155305 (2016). Evaluation of disorder introduced by electrolyte gating through transport measurements in graphene Andrew Browning, Norio Kumada, Yoshiaki Sekine, Hiroshi Irie, Koji Muraki, and Hideki Yamamoto Appl. Phys. Express 9, 065102 (2016). Shot noise generated by graphene p-n junctions in the quantum Hall effect regime N. Kumada, F. D. Parmentier, H. Hibino, D. C. Glattli, and P. Roulleau Nature Commun. 6, 8068 (2015). Resonant Edge Magnetoplasmons and Their Decay in Graphene N. Kumada, P. Roulleau, B. Roche, M. Hashisaka, H. Hibino, I. Petkovic, and D. C. Glattli Phys. Rev. Lett. 113, 266601 (2014). Effects of screening on the propagation of graphene surface plasmons Ken-ichi Sasaki and Norio Kumada Phys. Rev. B 90, 035449 (2014). Plasmon transport and its guiding in graphene Norio Kumada, Romain Dubourget, Ken'ichi Sasaki, Shinichi Tanabe, Hiroki Hibino, Hiroshi Kamata, Masayuki Hashisaka, Koji Muraki, Toshimasa Fujisawa New J. Phys. 16, 063055 (2014). Fractionalized wave packets from an artificial Tomonaga-Luttinger liquid H. Kamata, N. Kumada, M. Hashisaka, K. Muraki, and T. Fujisawa, Nature Nanotech. 9, 177 (2014). Distributed-element circuit model of edge magnetoplasmon transport Masayuki Hashisaka, Hiroshi Kamata, Norio Kumada, Kazuhisa Washio, Ryuji Murata, Koji Muraki, and Toshimasa Fujisawa Phys. Rev. B 88, 235409 (2013). Tunable plasmons in graphene N. Kumada, S. Tanabe, H. Hibino, H. Kamata, M. Hashisaka, K. Muraki, and T. Fujisawa SPIE Newsroom Plasmon Transport in Graphene Norio Kumada NTT Technical Review August 2013 Vol. 11 No. 8 Plasmon transport in graphene investigated by time-resolved electrical measurements N. Kumada, S. Tanabe, H. Hibino, H. Kamata, M. Hashisaka, K. Muraki, and T. Fujisawa Nature Commun. 4, 1363 (2013). All electrical probe of nuclear spin polarization and relaxation by spin phase transition peaks of the filling fraction nu=2/3 quantum hall effect M. H. Fauzi, S. Watanabe, N. Kumada, and Y. Hirayama J. Korean Physical Soc. 60, 1676 (2012). Unraveling the Spin Polarization of the nu = 5/2 Fractional Quantum Hall State L. Tiemann, G. Gamez, N. Kumada, and K. Muraki Science 335, 828 (2012). Low-frequency spin fluctuations in skyrmions confined by wires: Measurements of local nuclear spin relaxation Takashi Kobayashi, Norio Kumada, Takeshi Ota, Satoshi Sasaki, and Yoshiro Hirayama Phys. Rev. Lett. 107, 126807 (2011). Edge magnetoplasmon transport in gated and ungated quantum Hall systems N. Kumada, H. Kamata, and T. Fujisawa Phys. Rev. B 84, 045314 (2011). Dynamical d-wave condensation of exciton-polaritons in a two-dimensional square-lattice potential Na Young Kim, Kenichiro Kusudo, Congjun Wu, Naoyuki Masumoto, Andreas Löffler, Sven Höfling, Norio Kumada, Lukas Worschech, Alfred Forchel, and Yoshihisa Yamamoto Nature Phys. 7, 681 (2011). Field and Density Dependence of Edge Magnetoplasmon Transport in a Quantum Hall System N. Kumada, H. Kamata, K. Muraki, and T. Fujisawa J. Phys.: Conf. Ser. 334 012032 (2011). High-sensitive optical measurement of spin polarization in a quantum Hall system H. Ito, T. Yamazaki, D. Fukuoka, K. Oto, K. Muro, Y. Hirayama, and N. Kumada J. Phys.: Conf. Ser. 334 012021 (2011). Spin polarization in quantum Hall state obtained by Kerr rotation spectra H. Ito, M. Seo, D. Fukuoka, K. Oto, K. Muro, Y. Hirayama, and N. Kumada AIP Conf. Proc. 1399, 637 (2011). Anisotropy of Magnetoresistance Hysteresis around the nu=2/3 Quantum Hall State in Tilted Magnetic Field K. Iwata, M. Morino, A. Fukuda, N. Kumada, Z. F. Ezawa, Y. Hirayama, and A. Sawada J. Phys. Soc. Jpn. 79, 123701 (2010). Skyrmion effect on the relaxation of spin waves in a quantum Hall ferromagnet D. Fukuoka, K. Oto, K. Muro, Y. Hirayama, and N. Kumada Phys. Rev. Lett. 105, 126802 (2010). Nuclear spin polarization and relaxation probed by spin phase transition peak S. Watanabe, M. H. Fauzi, N. Kumada, and Y. Hirayama Phys. Status Solidi C 7, 2570 (2010). Activation study of collective excitations of the soliton-lattice phase in the nu=1 double-layer quantum Hall state D. Terasawa, S. Kozumi, A. Fukuda, M. Morino, K. Iwata, N. Kumada, Y. Hirayama, Z. F. Ezawa and A. Sawada Phys. Rev. B 81, 073303 (2010). Intrinsic gap and exciton condensation in the nu_T=1 bilayer system P. Giudici, K. Muraki, N. Kumada, and T. Fujisawa Phys. Rev. Lett. 104, 056802 (2010). >>abstract Spectroscopic study of nuclear magnetic resonance induced by oscillating electron spin domainw alls S.Watanabe, G.Igarashi, K. Hashimoto, N.Kumada, and Y. Hirayama Physica E 42, 999 (2010). Nuclear Spin Resonance Induced by Radio Frequency Electric Field N. Kumada, T. Kamada, Y. Hirayama, S. Miyashita, and T. Fujisawa AIP Conf. Proc. 1199, 461 (2010). Selective polarization of nuclear spins in a wire-like quantum Hall system T. Kobayashi, N. Kumada, T. Ota, S. Sasaki and Y. Hirayama AIP Conf. Proc. 1199, 241 (2010). Time-Resolved Kerr Rotation Spectroscopy of Spin Dynamics in a Quantum Hall System D. Fukuoka, N. Tanaka, K. Oto, K. Muro, Y. Hirayama, N. Kumada, and H. Yamaguchi AIP Conf. Proc. 1199, 243 (2010). Spin effects in the phase transition of the nu_T=1 bilayer electron system K. Muraki, P. Giudici, and N. Kumada Int. J. Mod. Phys. B 23, 2587 (2009). Electron spin imaging in quantum Hall devices by Kerr rotation measurement K. Oto ,R. Inaba, T. Yamada, T. Yamazaki, K. Muro, Y. Hirayama, N. Kumada and H. Yamaguchi Int. J. Mod. Phys. B 23, 2705 (2009). Optically induced nuclear spin polarization in quantum Hall regime observed by a time-resolved Kerr rotation D. Fukuoka, N. Tanaka, K. Oto, K. Muro, Y. Hirayama, N. Kumada, H. Yamaguchi Int. J. Mod. Phys. B 23, 2755 (2009). Activation study of the pseudospin soliton in the nu=1 bilayer quantum Hall effect A. Fukuda, D. Terasawa, M. Morino, K. Iwata, S. Kozumi, T. Sekikawa, Y. Ogasawara, T. Arai, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada J. Phys.: Conf. Ser. 150, 022012 (2009). Electron-spin/nuclear-spin interactions and NMR in semiconductors Y. Hirayama, G. Yusa, K. Hashimoto, N. Kumada, T. Ota, and K. Muraki Semicond. Sci. Technol. 24, 023001 (2009). Semiconductor Science & Technology Highlights of 2009 Electric-Field-Induced Nuclear Spin Resonance Mediated by Oscillating Electron Spin Domains in GaAs-Based Semiconductors N. Kumada, T. Kamada, S. Miyashita, Y. Hirayama, T. Fujisawa Phys. Rev. Lett. 101, 137602 (2008). >>abstract Observation of Bogoliubov excitations in exciton-polariton condensates S. Utsunomiya, L. Tian, G. Roumpos, C. W. Lai, N. Kumada, T. Fujisawa, M. Kuwata-Gonokami, A. Loffler, S. Hofling, A. Forchel, and Y. Yamamoto Nature Physics 4, 700 (2008). >>abstract Spin Dynamics of Two-Dimensional Electrons in a Quantum Hall System Probed by Time-Resolved Kerr Rotation Spectroscopy D. Fukuoka, T. Yamazaki, N. Tanaka, K. Oto, K. Muro, Y. Hirayama, N. Kumada, and H. Yamaguchi Phys. Rev. B 78, 041304(R) (2008). >>abstract GaAs microcavity exciton-polaritons in a trap Na Young Kim, Chih-Wei Lai, Shoko Utsunomiya, Georgios Roumpos, Hui Deng, Tim Byrnes, Patrik Recher, Norio Kumada, Toshimasa Fujisawa, and Yoshihisa Yamamoto Phys. Stat. Sol. (b) 245, 1076 (2008). Modulation of bilayer quantum Hall states by tilted-field-induced subband-Landau-level coupling N. Kumada, K. Iwata, K. Tagashira, Y. Shimoda, K. Muraki, Y. Hirayama, and A. Sawada Phys. Rev. B. 77, 155324 (2008). >>abstract Boundary-mediated electron-electron interactions in quantum point contacts V. T. Renard, O. A. Tkachenko, V. A. Tkachenko, T. Ota, N. Kumada, J-C Portal, and Y. Hirayama Phys. Rev. Lett. 100, 186801 (2008). >>abstract Spin-dependent phase diagram of the nu_T=1 bilayer electron system P. Giudici, K. Muraki, N. Kumada, Y. Hirayama, and T. Fujisawa Phys. Rev. Lett. 100, 106803 (2008). >>abstract NMR Study of a Canted Antiferromagnet in a Bilayer Quantum Hall System N. Kumada, K. Muraki, and Y. Hirayama Physica E 40, 937 (2008). Electron-electron interactions in clean quantum point contacts in the large conductance regime V. T. Renard, O. A. Tkachenko, V. A. Tkachenko, T. Ota, N. Kumada, J. C. Portal, and Y. Hirayama Physica E 40, 1684 (2008). Effects of In-plane Magnetic Field Direction on the Nuclear Spin Relaxation in the nu=2/3 Quantum Hall State K. Iwata, M. Moriono, A. Fukuda, A. Sawada, M. Suzuki, Z. F. Ezawa, N. Kumada, and Y. Hirayama Physica E 40, 1175 (2008). Anisotropic Magnetotransport by the Psudospin Soliton in the Bilayer nu=1 Quantum Hall System A. Fukuda, M. Morino, K. Iwata, D. Terasawa, S. Kozumi, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada Physica E 40, 1255 (2008). Activation Study of the Bilayer nu=1/3 Quantum Hall State A. Fukuda, K. Iwata, T. Sekikawa, T. Arai, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada Physica E 40, 1261 (2008). Initialization and logic gate operations of nuclear spin qubits using a submicron scale resistively-detected NMR device T. Ota, G. Yusa, N. Kumada, S. Miyashita, and Y. Hirayama Phys. Stat. Sol. (c) 5, 306 (2008). Nuclear-spin-based Quantum Information Devices in Solid-State Nanometer-Scale Structures Norio Kumada, Takeshi Ota, and Koji Muraki NTT Technical Review January 2008 Vol. 6 No. 1 Coherence Time of Nuclear Spins in GaAs Quantum Well Probed by Submicron-Scale All-Electrical Nuclear Magnetic Resonance Device Takeshi Ota, Norio Kumada, Go Yusa, Sen Miyashita, Toshimasa Fujisawa, and Yoshiro Hirayama Jpn. J. Appl. Phys. 47, 3115 (2008). Pseudospin soliton in the nu=1 bilayer quantum Hall state A. Fukuda, D. Terasawa, M. Morino, K. Iwata, S. Kozumi, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada Phys. Rev. Lett. 100, 016801 (2008). >>abstract Positive magneto-resistance in a point contact: possible manifestation of interactions V. T. Renard, T. Ota, N. Kumada, and Y. Hirayama International Journal of High Speed Electronics and Systems 17, 495 (2007). Decoherence of nuclear spins due to dipole-dipole interactions probed by resistively detected nuclear magnetic resonance T. Ota, G. Yusa, N. Kumada, S. Miyashita, T. Fujisawa, and Y. Hirayama Appl. Phys. Lett. 91, 193101 (2007). >>abstract Coherent zero-state and pi-state in an exciton-polariton condensate array C. W. La, N. Y. Kim, S. Utsunomiya, G. Roumpos, H. Deng, M. D. Fraser, T. Byrnes, P. Recher, N. Kumada, T. Fujisawa, and Y. Yamamoto Nature 450, 529 (2007). >>abstract NMR Evidence for Spin Canting in a Bilayer nu=2 Quantum Hall System N. Kumada, K. Muraki, and Y. Hirayama Phys. Rev. Lett. 99, 076805 (2007). >>abstract Anisotropy of Current-pumped Nuclear Spin Polarization in the nu=2/3 Quantum Hall State K. Iwata, M. Moriono, A. Fukuda, A. Sawada, M. Suzuki, Z. F. Ezawa, N. Kumada, and Y. Hirayama AIP Conference Proceedings 893, 643 (2007). Effects of In-plane Magnetic Fields on the Canted Antiferromagnetic Phase in the Bilayer nu=2 Quantum Hall State A. Fukuda, S. Kozumi, D. Terasawa, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada AIP Conference Proceedings 893, 639 (2007). Interaction of Electron and Nuclear Spins in Quantum Wells K. Muraki, N. Kumada, and Y. Hirayama Int. J. Mod. Phys. B 21, 1266 (2007). Nuclear spin population and its control toward initialization using an all-electrical sub-micron scale nuclear magnetic resonance device T. Ota, G. Yusa, N. Kumada, S. Miyashita, and Y. Hirayama Appl. Phys. Lett. 90, 102118 (2007). >>abstract Study of nuclear quadrupolar interaction using a novel all-electrical GaAs NMR device T. Ota, N. Kumada, G. Yusa, S. Miyashita, and Y. Hirayama Phys. Stat. Sol. (c) 4, 1759 (2007). In-plane Field Induced Anisotropic Behavior of Hysteresis in the nu=2/3 Quantum Hall State K. Iwata, A. Fukuda, A. Sawada, M. Moriono, Z. F. Ezawa, M. Suzuki, N. Kumada, and Y. Hirayama Proceedings of MS+S Phase Diagram of the nu=2 Bilayer Quantum Hall State A. Fukuda, A. Sawada, K. Iwata, S. Kozumi, D. Terawasa, Y. Shimoda, Z. F. Ezawa, N. Kumada, and Y. Hirayama Proceedings of MS+S Low-Frequency Spin Dynamics in a Canted Antiferromagnet N. Kumada, K. Muraki, and Y. Hirayama Science 313, 329 (2006). >>abstract Nuclear-spin-lattice relaxation in a nu=1 bilayer quantum Hall state N. Kumada, K. Muraki, and Y. Hirayama Physica E 34, 164 (2006). Anisotropic magnetotransport near the nu=2/3 quantum Hall state M. Morino, K. Iwata, M. Suzuki, A. Fukuda, A. Sawada, Z. F. Ezawa, N. Kumada, and Y. Hirayama Physica E 34, 152 (2006). Stability of Soliton Lattice phase in the nu=1 Bilayer Quantum Hall State under Tilted Magnetic Fields D. Terasawa, A. Fukuda, S. Kozumi, Z. F. Ezawa, A. Sawada, N. Kumada, and Y. Hirayama Physica E 34, 81 (2006). Quantum Transport Study of a Canted Antiferromagnetic Phase in nu=2 Bilayer Quantum Hall State A. Fukuda, S. Kozumi, D. Terasawa, Y. Shimoda, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada Physica E 34, 77 (2006). Magnetotransport Study of the Canted Antiferromagnetic Phase in Bilayer nu=2 Quantum Hall State A. Fukuda, S. Kozumi, D. Terasawa, Y. Shimoda, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada Phys. Rev. B 73, 165304 (2006). Magnetoresistance Peak in the nu=2 Bilayer Quantum Hall State under Tilted Magnetic Field A. Fukuda, S. Kozumi, D. Terasawa, N. Kumada, Y. Hirayama, Z. F. Ezawa, and A. Sawada AIP Conference Proceedings 850, LT24, 1337 (2006). Anisotropic behavior of hysterestic transport phenomena in the nu=2/3 quantum Hall state in the tilted magnetic field K. Iwata, M. Morino, A. Fukuda, A. Sawada, Z. F. Ezawa, M. Suzuki, N. Kumada, and Y. Hirayama AIP Conference Proceedings 850, LT24, 1339 (2006). Anisotropic Magnetotransport Near The Bilayer nu=2/3 Quantum Hall State M. Morino, K. Iwata, M. Suzuki, A. Fukuda, A. Sawada, Z. F. Ezawa, N. Kumada, and Y. Hirayama AIP Conference Proceedings 850, LT24, 1335 (2006). Effects of inversion asymmetry on electron-nuclear spin coupling in semiconductor heterostructures: A possible role of spin-orbit interactions K. Hashimoto, K. Muraki, N. Kumada, and Y. Hirayama Phys. Rev. Lett. 94, 146601 (2005). >>abstract Pseudospin domain of nu=1 double-layer quantum Hall state near commensurate-incommensurate transition D. Terasawa, S. Kozumi, A. Fukuda, A. Sawada, Z. F. Ezawa, N. Kumada, and Y. Hirayama Journal of Physics and Chemistry of Solids 66, 1560 (2005). Anisotropic magnetotransport around the nu=1 bilayer quantum Hall state K. Iwata, M. Morino, M. Suzuki, A. Fukuda, A. Sawada, Z. F. Ezawa, N. Kumada, and Y. Hirayama Journal of Physics and Chemistry of Solids 66, 1556 (2005). Spin degree of freedom in the nu=1 bilayer electron system investigated by nuclear spin relaxation N. Kumada, K. Muraki, K. Hashimoto, and Y. Hirayama Phys. Rev. Lett. 94, 096802 (2005). >>abstract Strong to weak correlation phase transition at nu_T=1 in a bilayer system detected by nuclear-spin-relaxation time N. Kumada, K. Muraki, K. Hashimoto, T. Saku, and Y. Hirayama AIP Conf. Proc. 772 567 (2005). Double magnetoresistance minima for nu=1 quantum Hall state near commensurate-incommensurate transition D. Terasawa, K. Nakada, S. Kozumi, A. Fukuda, A. Sawada, Z. F. Ezawa, N. Kumada, K. Muraki, T. Saku, and Y. Hirayama AIP Conf. Proc. 772 563 (2005). In-plane filed induced anisotropy of the longitudinal resistance in a bilayer quantum Hall system M. Morino, K. Iwata, M. Suzuki, A. Fukuda, A. Sawada, Z. F. Ezawa, N. Kumada, K. Muraki, T. Saku, and Y. Hirayama AIP Conf. Proc. 772 565 (2005). Duoble magnetoresistance minima induced by the in-plane magnetic field for the nu=1 double-layer quantum Hall st ate D. Terasawa, K. Nakada, S. Kozumi, Z. F. Ezawa, A. Fukuda, A. Sawada, N. Kumada, K. Muraki, T. Saku, and Y. Hirayama Int. J. Mod. Phys. B 18, 3709 (2004). Anisotropic transport on the nu=1 bilayer quantum Hall system under tilted magnetic filed M. Morino, K. Iwata, M. Suzuki, Z. F. Ezawa, A. Sawada, N. Kumada, K. Muraki, T. Saku, and Y. Hirayama Int. J. Mod. Phys. B 18, 3705 (2004). Phase diagrams of nu=2 and nu=2/3 quantum Hall states in bilayer systems N. Kumada, D. Terasawa, M. Morino, K. Tagashira, A. Sawada, E. F. Ezawa, K. Muraki, Y. Hirayama and T. Saku Phys. Rev. B 69, 155319 (2004). >>abstract Simultaneous excitation of spins and pseudospins in the bilayer nu=1 quantum hall state D. Terasawa, M. Morino, K. Nakada, S. Kozumi, A. Sawada, Z. F. Ezawa, N. Kumada, K. Muraki, T. Saku and Y. Hirayama Physica E 22, 52 (2004). Effects of in-plane magnetic fields on spin transitions in bilayer quantum Hall states N. Kumada, K. Tagashira, K. Iwata, A. Sawada, Z. F. Ezawa, K. Muraki, T. Saku and Y. Hirayama Physica E 22, 36 (2004). Continuous transformation from spin- to pseudospin-type excitation A. Sawada, D. Terasawa, N. Kumada, M. Morino, K. Tagashira, Z. F. Ezawa, K. Muraki, T. Saku and Y. Hirayama Physica E 18, 118 (2003). Composite fermion interactions in bilayer nu=2/3 quantum Hall states N. Kumada, Y. Shimoda, M. Morino, A. Sawada, E. F. Ezawa, K. Muraki, T. Saku, and Y. Hirayama Proceedings of ICPS-26 Phase diagram of interacting composite fermions in the bilayer nu=2/3 quantum Hall effect N. Kumada, D. Terasawa, Y. Shimoda, H. Azuhata, A. Sawada, E. F. Ezawa, K. Muraki, T. Saku and Y. Hirayama Phys. Rev. Lett. 89, 116802 (2002). >>abstract Integer and fractional quantum Hall effects in bilayer electron systems Z. F. Ezawa, A. Sawada and N. Kumada J. Phys. Chem. Solid 63, 1298 (2002). Various phase transitions in nu=2/3 bilayer quantum Hall states N. Kumada, D. Terasawa, Y. Shimoda, H. Azuhata, A. Sawada, E. F. Ezawa, K. Muraki, T. Saku and Y. Hirayama Physica E 12, 32 (2002). Preferred number of flipped spins in Skyrmion excitation N. Kumada, A. Sawada, E. F. Ezawa, H. Azuhata, S. Nagahama, K. Muraki, T. Saku and Y. Hirayama Physica B 298, 169 (2001). Skyrmion excitations in monolayer nu=1 and bilayer nu=2 quantum Hall states N. Kumada, A. Sawada, E. F. Ezawa, S. Nagahama, H. Azuhata, and T. Saku Proceedings of ICPS-25 Doubly enhanced skyrmions in nu=2 bilayer quantum Hall states N. Kumada, A. Sawada, E. F. Ezawa, H. Azuhata, S. Nagahama, K. Muraki, T. Saku and Y. Hirayama J. Phys. Soc. Jpn. 69, 3178 (2000). >>abstract n(+)-GaAs back-gated double-quantum-well structures with full density control K. Muraki, N. Kumada T. Saku and Y. Hirayama Jpn. J. Appl. Phys. 39, 2444 (2000). Bilayer nu=2 quantum Hall state in parallel high magnetic field A. Sawada, E. F. Ezawa, H. Ohno, Y. Horikoshi, N. Kumada, Y. Ohno, S. Kishimoto, F. Matsukura and S. Nagahama Physica E 6, 615 (2000). Interlayer charge transfer in bilayer quantum Hall states at various filling factors K. Muraki, T. Saku, Y. Hirayama, N. Kumada, A. Sawada and Z. F. Ezawa Solid State Commun. 112, 625 (1999). Interlayer coherence in nu=1 and nu=2 bilayer quantum Hall states A. Sawada, E. F. Ezawa, H. Ohno, Y. Horikoshi, A. Urayama, Y. Ohno, S. Kishimoto, F. Matsukura and N. Kumada Phys. Rev. B 59, 14888 (1999). Illustrations Oiseaux de France