Directing Nuclear Spin Flips in InAs Quantum Dots Using Detuned Optical Pulse Trains

Carter, Sam; Shabaev, A.; Economou, Sophia E.; Kennedy, T. A.; Bracker, Allan S.; Reinecke, T. L.

doi:10.1103/physrevlett.102.167403

Cited by 57 publications

(101 citation statements)

References 43 publications

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“…The asymmetry discussed above does not require the inclusion of nuclear spin effects to describe the shifts of ellipticity and Faraday rotation signals from zero detuning, as was suggested in Ref. 12.…”

Section: B Illustrative Examplementioning

confidence: 92%

Effect of pump-probe detuning on the Faraday rotation and ellipticity signals of mode-locked spins in (In,Ga)As/GaAs quantum dots

et al. 2010

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We have studied the Faraday rotation and ellipticity signals in ensembles of singly-charged (In,Ga)As/GaAs quantum dots by pump-probe spectroscopy. For degenerate pump and probe we observe that the Faraday rotation signal amplitude first grows with increasing the time separation between pump and probe before a decay is observed for large temporal separations. The temporal behavior of the ellipticity signal, on the other hand, is regular: its amplitude decays with the separation. By contrast, for detuned pump and probe the Faraday rotation and ellipticty signals both exhibit similar and conventional behavior. The experimental results are well described in the frame of a recently developed microscopic theory [Phys. Rev. B 80, 104436 (2009)]. The comparison between calculations and experimental data allows us to provide insight into the spectral dependence of the electron spin precession frequencies and extract the electron g factor dependence on energy.

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Section: B Illustrative Examplementioning

confidence: 92%

Effect of pump-probe detuning on the Faraday rotation and ellipticity signals of mode-locked spins in (In,Ga)As/GaAs quantum dots

et al. 2010

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“…This is responsible for the experimentally observed suppression of the nuclear field fluctuation and hence prolonged electron-spin coherence time. [69][70][71][72][73][75][76][77] Our key finding is that all the above controls can be quantified concisely by the nonlinear nuclear field feedback function H(h), which is defined for a single cycle of the feedback loop. Physically, this nonlinear feedback function encapsulates the mutual response between the nuclear field and the e-h system.…”

Section: Systematic Microscopic Theory For General Feedback Loopmentioning

confidence: 99%

“…Recently, several experimental groups reported significant suppression of the nuclear field fluctuation for weakly or moderately polarized nuclear spins in QD ensembles, 69,70 two coupled quantum dots [71][72][73][74] and, in particular, single quantum dots, [75][76][77] an important configuration for quantum computation. In single quantum dots, [75][76][77][78] the key experimental observation is the maintenance (i.e., locking) of resonant absorption over a range of pump frequencies around the natural resonance.…”

Section: A Electron-or Hole-induced Nuclear Spin Flip and Feedbackmentioning

confidence: 99%

“…Such feedback processes correlate the dynamics of different nuclear spins and play a critical role in suppressing the nuclear field fluctuation and hence prolonging the electron-spin coherence time. In particular, all experimentally reported [69][70][71][72][73][75][76][77] suppressions of the nuclear field fluctuation occur in weakly or moderately polarized systems and are attributed to feedback processes [ Fig. 2(a)] instead of a strong nuclear spin polarization.…”

Section: Fig 2 (Color Online) (A)mentioning

confidence: 99%

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General theory of feedback control of a nuclear spin ensemble in quantum dots

Yang

Sham

2013

Phys. Rev. B

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We present a microscopic theory of the nonequilibrium nuclear spin dynamics driven by the electron and/or hole under continuous-wave pumping in a quantum dot. We show the correlated dynamics of the nuclear spin ensemble and the electron and/or hole under optical excitation as a quantum feedback loop and investigate the dynamics of the many nuclear spins as a nonlinear collective motion. This gives rise to three observable effects: (i) hysteresis, (ii) locking (avoidance) of the pump absorption strength to (from) the natural resonance, and (iii) suppression (amplification) of the fluctuation of weakly polarized nuclear spins, leading to prolonged (shortened) electron-spin coherence time. A single nonlinear feedback function is constructed which determines the different outcomes of the three effects listed above depending on the feedback being negative or positive. The general theory also helps to put in perspective the wide range of existing theories on the problem of a single electron spin in a nuclear spin bath.

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“…role of dynamic nuclear polarization (DNP) in TMDs has not been investigated so far, despite its striking effects in other low dimensional semiconductor systems [34][35][36][37][38][39][40][41][42][43][44] .…”

Section: Introductionmentioning

confidence: 99%

Interplay of valley polarization and dynamic nuclear polarization in 2D transition metal dichalcogenides

2017

Self Cite

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The interplay of Ising spin-orbit coupling and non-trivial band topology in transition metal dichalcogenides (TMDs) produces anomalous transport and optical properties that are very different from a regular 2D electron gas. The spin-momentum locking of optically excited carriers near a valley point can give rise to an anomalous spin-valley Hall current under the application of an in-plane electric field. TMDs also exhibit strong electronnuclear hyperfine interactions, but their effect on spin-valley-locked currents remains unknown. Here, we show that hyperfine interactions can create a feedback mechanism in which spin-valley currents generate significant dynamical nuclear polarization which in turn Zeeman shifts excitonic transitions out of resonance with an optical driving field, saturating the production of spin-valley polarization. We propose an experimental signature of dynamic nuclear polarization which can be detected via measurements of the anomalous Hall current. Our results help to elucidate the interplay of valley polarization and nuclear spin dynamics in TMDs.

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Directing Nuclear Spin Flips in InAs Quantum Dots Using Detuned Optical Pulse Trains

Cited by 57 publications

References 43 publications

Effect of pump-probe detuning on the Faraday rotation and ellipticity signals of mode-locked spins in (In,Ga)As/GaAs quantum dots

Effect of pump-probe detuning on the Faraday rotation and ellipticity signals of mode-locked spins in (In,Ga)As/GaAs quantum dots

General theory of feedback control of a nuclear spin ensemble in quantum dots

Interplay of valley polarization and dynamic nuclear polarization in 2D transition metal dichalcogenides

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