Koji Muraki (NTT Basic Research Labs)

Japanese/English

		Koji Muraki, Dr. - Senior Research Scientist, Distinguished Technical Member, Group Leader -
		Quantum Solid State Physics Research Group NTT Basic Research Laboratories 3-1 Morinosato-Wakamiya, Atsugi 243-0198, Japan E-mail: murakiwill.brl.ntt.co.jp
		1994.4-Present	NTT Basic Research Laboratories
		2001.8-2002.3	Guest Scientist at Max-Planck-Insititut, Stuttgart
		1994.3	Ph.D, University of Tokyo

What's New

[2010.08.01] 19th Int. Conf. on High Magnetic Fields in Semiconductor Physics (HMF-19) to be held in Fukuoka, Japan
[2009.07.21] A contributed paper on the intrinsic gap of bilayer nu=1 system presented at EP2DS in Kobe, Japan
[2009.06.25] Invited talk presented at EPQHS3 (Lucca, Italy)
[2009.04.07] New members, Dr. Keiko Takase and Dr. Kenichi Hitachi, join our group
[2009.04.01] A new member, Dr. Lars Tiemann, joins our group
[2009.04.01] Distinguished technical member of NTT Basic Research Laboratories
[2009.03.16] Invited talk presented at APS March meeting in Pittsburgh
[2009.01.21] A poster on double quantum point contact presented at ISNTT2009 in Atsugi
[2008.09.01] Group leader of Quantum Solid State Physics Research Group
[2008.08.04] Invited talk on the bilayer nu=1 system presented at HMF-18 in Sao Pedro
[2008.08.01] A paper on double quantum point contact presented at ICPS-2008 in Rio de Janeiro
[2008.03.13] A new member, Dr. Gerardo Gamez, joins our group
[2008.03.12] Dr. Paula Giudici's paper on the bilayer nu=1 system published in Physical Review Letters

Research Interests

Electron correlation and quantum coherence in semiconductor nanostructures
Many-body effects in single-layer and bilayer quantum Hall systems (spin effects, quantum Hall ferromagnetism, phase transitions, broken symmetry, and collective excitations)
Electron-nuclear spin interactions in semiconductor nanostructures
Coulomb drag between 2DEGs
Growth of high-mobility two-dimensional electron system (2DES) and hole system (2DHS)

Selected Publications

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]
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]
Exciton Condensate at a Total Filling Factor of One in Corbino Two-Dimensional Electron Bilayers
L. Tiemann, J. G. S. Lok, W. Dietsche, K. von Klitzing, K. Muraki, D. Schuh, and W. Wegscheider Phys. Rev. B 77, 033306 (2008). [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]
Low-Frequency Spin Dynamics in a Canted Antiferromagnet
N. Kumada, K. Muraki , and Y. Hirayama Science 313, 329 (2006). [abstract]
Controlled Multiple Quantum Coherences of Nuclear Spins in a Nonometre-Scale Device
G. Yusa, K. Muraki, K. Takashina, K. Hashimoto, and Y. Hirayama Nature 434, 1001 (2005). [abstract]
Effects of Inversion Asymmetry on Electron-Nuclear Spin Coupling in Semiconductor Heterostructures: Possible role of spin-orbit interactions
K. Hashimoto, K. Muraki, N. Kumada, T. Saku, and Y. Hirayama Phys. Rev. Lett 94, 146601 (2005). [abstract]
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]
Coulomb Drag as a Probe of the Nature of Compressible States in a Magnetic Field
K. Muraki, J. G. S. Lok, S. Kraus, W. Dietsche, K. von Klitzing, D. Schuh, M. Bichler, W. Wegscheider Phys. Rev. Lett. 92, 246801 (2004). [abstract]
Electrically Controlled Nuclear Spin Polarization and Relaxation by Quantum Hall States
K. Hashimoto, K. Muraki, T. Saku, and Y. Hirayama Phys. Rev. Lett. 88, 176601 (2002). [abstract]
Phase diagram of interacting composite fermion in the bilayer nu = 2/3 quantum Hall effect
N. Kumada, D. Terasawa, Y. Shimoda, H. Azuhata, A. Sawada, Z. F. Ezawa, K. Muraki, T. Saku, and Y. Hirayama Phys. Rev. Lett. 89, 116802 (2002). [abstract]
Spin polarization of fractional quantum Hall edge channels studied by dynamic nuclear polarization
T. Machida, S. Ishizuka, T. Yamazaki, S. Komiyama, K. Muraki, and Y. Hirayama Phys. Rev. B 65, 233304 (2002). [abstract]
Charge Excitations in Easy-Axis and Easy-Plane Quantum Hall Ferromagnets
K. Muraki, T. Saku, and Y. Hirayama Phys. Rev. Lett. 87, 196801 (2001). [abstract]
n(+)-GaAs Back-Gated Double-Quantum-Well Structures with Full Density Contorol
K. Muraki, N. Kumada, T. Saku, and Y. Hirayama Jpn. J. Appl. Phys. 39, 2444 (2000). [abstract]
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).
Spin Transition of a Two-Dimensional Hole System in the Fractional Quantum Hall Effect
K. Muraki and Y. Hirayama Phys. Rev. B 59, R2502 (1999). [abstract]
Effect of Valence Band Structure on the Fractional Quantum Hall Effect of Two-Dimensional Hole Systems
K. Muraki and Y. Hirayama Physica B 249, 65 (1998).
Fermi-Level Effect on Ga Self-Diffusion Studied Using (69)GaAs/(69)Ga(71)GaAs Isotope Superlattice
K. Muraki and Y. Horikoshi Inst. Phys. Conf. 145, 547 (1996).
Evidence for Resonant Electron Capture and Charge Buildup in AlGaAs/GaAs Quantum Wells
K. Muraki, A. Fujiwara, S. Fukatsu, Y. Shiraki, and Y. Takahashi Phys. Rev. B 53, 15 477 (1996). [abstract]
Surface Segregation of In Atoms and its Influence on the Energy Levels in InGaAs/GaAs Quantum Wells
K. Muraki, S. Fukatsu, Y. Shiraki, and R. Ito Appl. Phys. Lett. 61, 557 (1992). [abstract]

Full List of Publications (Since 1992)

Invited Talks

Emerging Phenomena in Quantum Hall Systems (EPQHS3), Lucca, Italy, 2009;
-New lights on the ground-state phase diagrams of bilayer electron systems
APS March Meeting, Pittsburgh, 2009;
-"Spin-dependent phase diagram in bilayer 2D electron systems"
The 18th Int. Conf. on High Magnetic Fields in Semiconductor Physics (HMF18), Sao Pedro, Brazil, 2008;
-"Spin Effects in the Phase Transition of the nu_T=1 Bilayer Electron System "
Device and Process Technologies for Microelectronics, MEMS, Photonics, and Nanotechnology IV, Canberra, 2007;
-"Nuclear spin manipulation in semiconductor nanostructures"
APS March Meeting, Denver, 2007;
-"Low-frequency spin dynamics in a quantum Hall canted antiferromagnet"
Interactions, Excitations, and Broken Symmetry in Quantum Hall Systems (QHSyst06), Dresden, 2006;
-"Spin/charge fluctuations in quantum Hall bilayers -Nuclear spin relaxation and Coulomb drag"
The 17th Int. Conf. on High Magnetic Fields in Semiconductor Physics (HMF17), Wuerzburg, 2006;
-"Electron-nuclear spin interaction in quantum wells "
The 23th Int. Conf. Low Temperature Physics (LT23), Hiroshima, 2002;
-"Charge excitation and transport in pseudospin quantum Hall ferromagnets "

Gallery

8 Months in Stuttgart

What's New

Research Interests

Selected Publications

Invited Talks

Gallery

Links