Local Dynamic Nuclear Polarization Using Quantum Point Contacts

Wald, Keith; Kouwenhoven, L. P.; McEuen, Paul L.; Vaart, N.C. van der; Foxon, C.T.

doi:10.1103/physrevlett.73.1011

Cited by 166 publications

(173 citation statements)

References 10 publications

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“…In the experiments of Ref. [18], this was not done, leading to what we now believe is an incorrect interpretation of the relative importance of the flip-flop and Zeeman terms in the experiments. In particular, the hysteresis in Ref.…”

Section: Comparison With Our Earlier Experimentsmentioning

confidence: 89%

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Dynamic nuclear polarization at the edge of a two-dimensional electron gas

et al. 1997

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We have used gated GaAs/AlGaAs heterostructures to explore nonlinear transport between spin-resolved Landau level (LL) edge states over a submicron region of two-dimensional electron gas (2DEG). The current I flowing from one edge state to the other as a function of the voltage V between them shows diode-like behavior-a rapid increase in I above a well-defined threshold Vt under forward bias, and a slower increase in I under reverse bias. In these measurements, a pronounced influence of a current-induced nuclear spin polarization on the spin splitting is observed, and supported by a series of NMR experiments. We conclude that the hyperfine interaction plays an important role in determining the electronic properties at the edge of a 2DEG.

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Section: Comparison With Our Earlier Experimentsmentioning

confidence: 89%

“…In particular, the hysteresis in Ref. [18] was attributed entirely to the effects of flip-flop scattering, while we now feel that the influence of the nuclear Zeeman term was crucial to understand the experiments.…”

Section: Comparison With Our Earlier Experimentsmentioning

confidence: 99%

Dynamic nuclear polarization at the edge of a two-dimensional electron gas

et al. 1997

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“…It is expected then that the nuclear spin dynamics is dominated by coherent spin exchanges mediated by electrons [40,41]. Owing to rapid advances in the experimental facilities, the hyperfine interactions in QHE systems have recently attracted growing theoretical [41,42] and experimental [37][38][39] interest; this progress makes it feasible to handle the electron spinnuclear spin interactions with almost atomic precision.…”

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confidence: 99%

“…The electron gas then forms a nondissipative QHE fluid [35]; the Hall resistance exhibits a plateau at a value that is a multiple of e 2 /h, while the dissipativity of the conduction electron gas (the magnetoresistance) approaches zero. Nuclearspin thermalization/relaxation processes occur on the time scale denoted T 1 [32] which, experimentally, ranges from several minutes to half an hour [37][38][39]. It is expected then that the nuclear spin dynamics is dominated by coherent spin exchanges mediated by electrons [40,41].…”

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confidence: 99%

“…It is possible to generate by holographic and other methods [48][49][50][51] a narrow strip of conductance at each spin in turn, see Figure 1, and send a current of spin-polarized electrons through it. The observed current can be pre-calibrated to enable high certainty determination of whether there was a spin-exchange scattering event thus determining the nuclear spin's direction, resembling the spin-diode [38,52] techniques. Furthermore, one can extend the strip of conductance over several replicas of the spin chain, separated order of magnitude more than the spins, e.g., 1000Å.…”

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Quantum computation in quantum-Hall systems

1998

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We describe a quantum information processor (quantum computer) based on the hyperfine interactions between the conduction electrons and nuclear spins embedded in a two-dimensional electron system in the quantum-Hall regime. Nuclear spins can be controlled individually by electromagnetic pulses. Their interactions, which are of the spin-exchange type, can be possibly switched on and off pair-wise dynamically, for nearest neighbors, by controlling impurities. We also propose the way to feed in the initial data and explore ideas for reading off the final results.

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A study of the domain structure at the spin transition of the fractional quantum Hall effect

Stern

Dini

Freytag

et al. 2008

Physica Status Solidi (b)

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IntroductionThe spin degree of freedom plays an important role in the fractional quantum Hall effect (FQHE) [1]. It is responsible for a variety of phenomena such as phase transitions between different ground states, elementary spin excitations and interactions of the electronic system with the nuclei. This was initially not obvious since the first approach to solve this strongly correlated many-body problem considered all quantum Hall states at filling factors less than ν = 1 to be spin polarized [2]. Even though this indeed applies to fractional filling factors 1 m ν = / , where m is an odd integer, it was soon pointed out that for other fractional filling factors at sufficiently low densities, QH ground states with partial or zero spin polarization do exist [3].These states are energetically favorable whenever the exchange part of the Coulomb interaction becomes of the order of the Zeeman energy. Furthermore, at the transition, a domain pattern of differently polarized phases is believed to form [4][5][6][7]. In this review, we report on spectroscopic evidence for the existence of these domains, based on NMR and SAW (surface-acoustic wave) measurements. We focus primarily on the unpolarized-polarized phase transition at filling factor ν = 2/3, al-

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Local Dynamic Nuclear Polarization Using Quantum Point Contacts

Cited by 166 publications

References 10 publications

Dynamic nuclear polarization at the edge of a two-dimensional electron gas

Dynamic nuclear polarization at the edge of a two-dimensional electron gas

Quantum computation in quantum-Hall systems

A study of the domain structure at the spin transition of the fractional quantum Hall effect

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