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The dynamics of the coupled electron-nuclear spin system is studied in an ensemble of singly-charged (In,Ga)As/GaAs quantum dots (QDs) using periodic optical excitation at 1 GHz repetition rate. In combination with the electron-nuclei…

Mesoscale and Nanoscale Physics · Physics 2021-08-11 E. Evers , N. E. Kopteva , I. A. Yugova , D. R. Yakovlev , M. Bayer , A. Greilich

Sizable nuclear spin polarization is pumped in individual InP/GaInP dots in a wide range of external magnetic fields B_ext=0-5T by circularly polarized optical excitation. We observe nuclear polarization of up to ~40% at Bext=1.5T and…

We show that detuned optical pulse trains with a modest spectral width can polarize nuclear spins in InAs quantum dots. The pulse bandwidth is large enough to excite a coherent superposition of both electron spin eigenstates in these…

Quantum Physics · Physics 2015-05-27 S. G. Carter , Sophia E. Economou , A. Shabaev , A. S. Bracker

Recent radio frequency scanning tunneling spectroscopy (rf-STS) experiments have demonstrated nuclear and electron spin excitations up to $\pm12\hbar$ in a single molecular spin quantum dot (qudot). Despite the profound experimental…

We demonstrate methods to locally control the spin rotation of moving electrons in a GaAs channel. The Larmor frequency of optically-injected spins is modulated when the spins are dragged through a region of spin-polarized nuclei created at…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 M. E. Nowakowski , G. D. Fuchs , S. Mack , N. Samarth , D. D. Awschalom

We find that detuning an optical pulse train from electronic transitions in quantum dots controls the direction of nuclear spin flips. The optical pulse train generates electron spins that precess about an applied magnetic field, with a…

Quantum Physics · Physics 2015-05-13 S. G. Carter , A. Shabaev , Sophia E. Economou , T. A. Kennedy , A. S. Bracker , T. L. Reinecke

We investigate interactions between electrons and nuclear spins by using the resistance (Rxx) peak which develops near filling factor n = 2/3 as a probe. By temporarily tuning n to a different value, ntemp, with a gate, the Rxx peak is…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 K. Hashimoto , K. Muraki , T. Saku , Y. Hirayama

We study a mechanism by which nuclear hyperpolarization due to the polarization transfer from a microwave-pulse-controlled electron spin is suppressed. From analytical and numerical calculations of the unitary dynamics of multiple nuclear…

Quantum Physics · Physics 2024-03-12 Kento Sasaki , Eisuke Abe

We theoretically study the interplay of spin-orbit and hyperfine interactions in dynamical nuclear polarization in two-electron semiconductor double quantum dots near the singlet $(S)$ - triplet $(T_+)$ anticrossing. The goal of the scheme…

Mesoscale and Nanoscale Physics · Physics 2016-01-20 Marko J. Rančić , Guido Burkard

Dynamical magnetic and nuclear polarization in complex spin systems is discussed on the example of transfer of spin from exciton to the central spin of magnetic impurity in a quantum dot in the presence of a finite number of nuclear spins.…

Mesoscale and Nanoscale Physics · Physics 2015-06-04 Ramin M. Abolfath , Anna Trojnar , Bahman Roostaei , Thomas Brabec , Pawel Hawrylak

We propose to use the spin-blockade regime in double quantum dots to reduce nuclear spin polarization fluctuations in analogy with optical Doppler cooling. The Overhauser shift brings electron levels in and out of resonance, creating…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. S. Rudner , L. S. Levitov

Optically-induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a…

Mesoscale and Nanoscale Physics · Physics 2016-01-06 F. Heisterkamp , A. Greilich , E. A. Zhukov , E. Kirstein , T. Kazimierczuk , V. L. Korenev , I. A. Yugova , D. R. Yakovlev , A. Pawlis , M. Bayer

Magnetic noise of atomic nuclear spins is a major problem for solid state spin qubits. Highly-polarized nuclei would not only overcome this obstacle, but also make nuclear spins a useful quantum information resource. However, achieving…

Optical and electrical control of the nuclear spin system allows enhancing the sensitivity of NMR applications and spin-based information storage and processing. Dynamic nuclear polarization in semiconductors is commonly achieved in the…

Mesoscale and Nanoscale Physics · Physics 2014-09-09 G. Sallen , S. Kunz , T. Amand , L. Bouet , T. Kuroda , T. Mano , D. Paget , O. Krebs , X. Marie , K. Sakoda , B. Urbaszek

We analyze nuclear spin dynamics in quantum dots and defect centers with a bound electron under electron-mediated coupling between nuclear spins due to the hyperfine interaction ("J-coupling" in NMR). Our analysis shows that the Overhauser…

Mesoscale and Nanoscale Physics · Physics 2008-11-04 D. Klauser , W. A. Coish , Daniel Loss

We demonstrate a new method for electrical manipulation of nuclear spins utilizing dynamic nuclear polarization induced by quantum Hall effect breakdown. Nuclear spins are polarized and detected through the hyperfine interaction between a…

Mesoscale and Nanoscale Physics · Physics 2009-04-17 Minoru Kawamura , Hiroyuki Takahashi , Yoshiaki Hashimoto , Shingo Katsumoto , Tomoki Machida

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

The hyperpolarisation of nuclear spins within target molecules is a critical and complex challenge in magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) spectroscopy. Hyperpolarisation offers enormous gains in signal and…

Hanle effect is ubiquitous in the study of spin-related phenomena and has been used to determine spin lifetime, precession and transport in semiconductors. Here, we report an experimental observation of anomalous Hanle effect in individual…

Mesoscale and Nanoscale Physics · Physics 2009-10-12 O. Krebs , P. Maletinsky , T. Amand , B. Urbaszek , A. Lemaître , P. Voisin , X. Marie , A. Imamoglu

The coherent electron spin dynamics of an ensemble of singly charged (In,Ga)As/GaAs quantum dots in a transverse magnetic field is driven by periodic optical excitation at 1 GHz repetition frequency. Despite the strong inhomogeneity of the…

Mesoscale and Nanoscale Physics · Physics 2021-04-20 E. Evers , N. E. Kopteva , I. A. Yugova , D. R. Yakovlev , D. Reuter , A. D. Wieck , M. Bayer , A. Greilich
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