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Electrical polarization of nuclear spins is studied in a Corbino disk under a breakdown regime of the quantum Hall effect (QHE). Since the edge channels are completely absent in the Corbino disk, we conclude that the electric current…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Minoru Kawamura , Hiroyuki Takahashi , Satoru Masubuchi , Yoshiaki Hashimoto , Shingo Katsumoto , Kohei Hamaya , Tomoki Machida

We studied spatial distribution of dynamic nuclear polarization (DNP) in a Hall-bar device in a breakdown regime of the quantum Hall effect (QHE). We detected nuclear magnetic resonance (NMR) signals from the polarized nuclear spins by…

Mesoscale and Nanoscale Physics · Physics 2011-01-25 Minoru Kawamura , Kimitoshi Kono , Yoshiaki Hashimoto , Shingo Katsumoto , Tomoki Machida

We investigate dynamic nuclear polarization in quantum point contacts (QPCs) in the integer and fractional quantum Hall regimes. Following the application of a dc bias, fractional plateaus in the QPC shift symmetrically about half filling…

Mesoscale and Nanoscale Physics · Physics 2014-11-20 A. Kou , D. T. McClure , C. M. Marcus , L. N. Pfeiffer , K. W. West

We have developed a method for electrical polarization of nuclear spins in quantum Hall systems. In a breakdown regime of odd-integer quantum Hall effect (QHE), excitation of electrons to the upper Landau subband with opposite spin polarity…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. Kawamura , H. Takahashi , K. Sugihara , S. Masubuchi , K. Hamaya , T. Machida

Experiments suggest that nuclear spins play a significant role in the quantum Hall effect (QHE) near integer and fractional QHE spin transitions, but many of these phenomena still remain to be understood. Here we study theoretically the…

Mesoscale and Nanoscale Physics · Physics 2026-02-03 Haotian Zhou , Yuli Lyanda-Geller

Nuclear spins are polarized electrically in a breakdown regime of an odd-integer quantum Hall effect (QHE). Electron excitation to the upper Landau subband with the opposite spin polarity flips nuclear spins through the hyperfine…

Mesoscale and Nanoscale Physics · Physics 2008-07-04 M. Kawamura , H. Takahashi , S. Masubuchi , Y. Hashimoto , S. Katsumoto , K. Hamaya , T. Machida

We present dynamic nuclear polarization (DNP) in the simplest pseudospin quantum Hall ferromagnet (QHF) of an InSb two-dimensional electron gas with a large g factor using tilted magnetic fields. The DNP-induced amplitude change of a…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 H. W. Liu , K. F. Yang , T. D. Mishima , M. B. Santos , Y. Hirayama

Dynamic Nuclear Polarization (DNP) is to date the most effective technique to increase the nuclear polarization up to a factor $100,000$ opening disruptive perspectives for medical applications. In DNP, the nuclear spins are driven to an -…

Strongly Correlated Electrons · Physics 2015-08-26 Andrea De Luca , Alberto Rosso

Resistively detected NMR (RDNMR) based on dynamic nuclear polarization (DNP) in a quantum Hall ferromagnet (QHF) is a highly-sensitive method for the discovery of fascinating quantum Hall phases; however, the mechanism of this DNP and in…

Mesoscale and Nanoscale Physics · Physics 2017-04-25 K. F. Yang , K. Nagase , Y. Hirayama , T. D. Mishima , M. B. Santos , H. W. Liu

We consider the dynamic nuclear spin polarization (DNP) using two electrons in a double quantum dot in presence of external magnetic field and spin-orbit interaction, in various schemes of periodically repeated sweeps through the S-T+…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Izhar Neder , Mark S. Rudner , Bertrand I. Halperin

Spin current perpendicular to the electric current is investigated around Landau level filling factor $\nu=3$ in a GaAs/AlGaAs two-dimensional electron system. Measurements of dynamic nuclear polarization in the vicinity of the edge of a…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Yosuke Komori , Satoru Sakuma , Tohru Okamoto

Dynamic nuclear polarization (DNP) is a promising strategy for generating a significantly increased non-thermal spin polarization in nuclear magnetic resonance (NMR) applications thereby circumventing the need for strong magnetic fields.…

Quantum Physics · Physics 2015-07-15 Alexander Karabanov , Daniel Wisniewski , Igor Lesanovsky , Walter Köckenberger

Dynamic Nuclear Polarization (DNP) presently stands as the preferred strategy to enhance the sensitivity of nuclear magnetic resonance measurements, but its application relies on the use of high-frequency microwave to manipulate electron…

Mesoscale and Nanoscale Physics · Physics 2022-02-02 Carlos A. Meriles , Pablo R. Zangara

Nuclear electric resonance (NER) is based on nuclear magnetic resonance mediated by spatial oscillations of electron spin domains excited by a radio frequency (RF) electric field, and it allows us to investigate the spatial distribution of…

Mesoscale and Nanoscale Physics · Physics 2012-10-25 S. Watanabe , G. Igarashi , N. Kumada , Y. Hirayama

We study pumping of charge in a 2DEG in the quantum Hall regime at filling factor $\nu = 2$ (2 spin-split levels of the lowest Landau level). For pumping frequencies that match the Zeeman energy splitting, quantum pumping together with…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 M. Blaauboer

Dynamic nuclear polarization (DNP) is an out-of-equilibrium method for generating non-thermal spin polarization which provides large signal enhancements in modern diagnostic methods based on nuclear magnetic resonance. A particular instance…

We investigate the resistance enhancement state (RES) where the magnetoresistance of the $\nu = 2/3$ fractional quantum Hall state (FQHS) is increased with dynamic nuclear spin polarization (DNP) induced by a large electric current. After…

Mesoscale and Nanoscale Physics · Physics 2013-10-03 Shibun Tsuda , Minh-Hai Nguyen , Daiju Terasawa , Akira Fukuda , Anju Sawada

Repeated injection of spin polarized carriers in a quantum dot leads to the polarization of nuclear spins, a process known as dynamic nuclear spin polarization (DNP). Here, we report the first observation of p-shell carrier assisted DNP in…

Mesoscale and Nanoscale Physics · Physics 2016-03-23 C. F. Fong , Y. Ota , E. Harbord , S. Iwamoto , Y. Arakawa

We present a spectrum of experimental data on the fractional quantum Hall effect (FQHE) states in the first excited Landau level, obtained in an ultrahigh mobility two-dimensional electron system (2DES) and at very low temperatures and…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 W. Pan , J. S. Xia , H. L. Stormer , D. C. Tsui , C. Vicente , E. D. Adams , N. S. Sullivan , L. N. Pfeiffer , K. W. Baldwin , K. W. West

Dynamic Nuclear Polarization (DNP) is transforming NMR and MRI by significantly enhancing sensitivity through the transfer of polarization from electron spins to nuclear spins via microwave irradiation. However, the use of monochromatic…

Quantum Physics · Physics 2024-10-28 Mayur Jhamnani , Sajith V Sadasivan , Sheetal Kumar Jain , Asif Equbal
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