Detection of spin injection into a double quantum dot: Violation of magnetic-field-inversion symmetry of nuclear polarization instabilities

Rudner, Mark S.; Rashba, Emmanuel I.

doi:10.1103/physrevb.83.073406

Cited by 4 publications

(25 citation statements)

References 27 publications

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“…Finite DNP occurs due to a competition between (i) the HF-induced escape from the blocking states and (ii) another weaker inelastic escape mechanism such as co-tunneling or spin-orbit interaction -as in the works by Rudner et al [33][34][35][36] The induced DNP acts back on the electronic energy levels of the DQD, which in turn change the transition rates until the steady state is reached. Hence, we are dealing with a non-linear system with feedback present as illustrated in Fig.…”

Section: A Main Ideas Of This Work and Comparison To Previous Workmentioning

confidence: 99%

“…Rudner et al [33][34][35][36] include this effect as level broadening, whereas we allow for energy emission and absorption e.g. by phonons in the HF rates.…”

Section: A Main Ideas Of This Work and Comparison To Previous Workmentioning

confidence: 99%

“…The DNP acts back on the energy levels E(P ) via the Overhauser fields and, in turn, on both the HF spin-flip rates W and the tunneling rates Γ. In contrast, the weak inelastic escape mechanism [33][34][35][36] (lower branch) leaves the DNP unchanged. (b) A real-space example of a HF-induced escape process from a triplet to the right contact through a singlet S. This changes the DNP.…”

Section: Tunneling Outmentioning

confidence: 99%

“…31,[33][34][35][36][37]99 The idea behind Eq. (10) is to describe a competition between various rates that polarize the nuclear spins in opposite directions, which is different from the aforementioned competition between various escape paths.…”

Section: -36mentioning

confidence: 99%

“…Here we introduce this difference by having A L = A R , but keep the DNP P as a common quantity for both dots. [33][34][35]42 In principle, the DNP can be spatially inhomogeneous, which is challenging to model in detail. A step on that way, is having different -but homogeneous -polarizations in the two dots and A L = A R .…”

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confidence: 99%

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Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime

et al. 2013

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The interplay of dynamical nuclear polarization (DNP) and leakage current through a double quantum dot in the spin-blockade regime is analyzed. A finite DNP is built up due to a competition between hyperfine (HF) spin-flip transitions and another inelastic escape mechanism from the triplets, which block transport. We focus on the temperature dependence of the DNP for zero energy-detuning (i.e. equal electrostatic energy of one electron in each dot and a singlet in the right dot). Our main result is the existence of a transition temperature, below which the DNP is bistable, so a hysteretic leakage current versus external magnetic field B appears. This is studied in two cases: (i) Close to the crossing of the three triplet energy levels near B = 0, where spin-blockade is lifted due to the inhomogeneity of the effective magnetic field from the nuclei. (ii) At higher B-fields, where the two spin-polarized triplets simultaneously cross two different singlet energy levels. We develop simplified models leading to different transition temperatures Tc,tt and Tc,st for the crossing of the triplet levels and the singlet-triplet level crossings, respectively. We find Tc,tt analytically to be given solely by the HF couplings, whereas Tc,st depends on various parameters and Tc,st > Tc,tt. The key idea behind the existence of the transition temperatures at zero energy-detuning is the suppression of energy absorption compared to emission in the inelastic HF transitions. Finally, by comparing the rate equation results with Monte Carlo simulations, we discuss the importance of having both HF interaction and another escape mechanism from the triplets to induce a finite DNP.

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Section: A Main Ideas Of This Work and Comparison To Previous Workmentioning

confidence: 99%

“…Rudner et al [33][34][35][36] include this effect as level broadening, whereas we allow for energy emission and absorption e.g. by phonons in the HF rates.…”

Section: A Main Ideas Of This Work and Comparison To Previous Workmentioning

confidence: 99%

Section: Tunneling Outmentioning

confidence: 99%

Section: -36mentioning

confidence: 99%

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confidence: 99%

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Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime

et al. 2013

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Sensing Kondo correlations in a suspended carbon nanotube mechanical resonator with spin‐orbit coupling

Liu

2019

Quantum Engineering

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We study electron mechanical coupling in a suspended carbon nanotube (CNT) quantum dot device. An electron spin couples to the flexural vibration mode because of spin-orbit coupling in the electron tunneling processes. In the weak coupling limit, ie, electron-vibration coupling is much smaller than an electron energy scale, the damping and resonant frequency shift of the CNT resonator can be obtained by calculating the dynamical spin susceptibility. We find that strong spin-flip scattering processes in the Kondo regime significantly affect the mechanical motion of the carbon nanotube: The Kondo effect induces strong damping and frequency shift of the CNT resonator.KEYWORDS carbon nanotube, Kondo correlation, quantum nanomechanical resonator Quantum Engineering. 2019;1:e10.wileyonlinelibrary.com/journal/que2

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Suppression of Zeeman Gradients by Nuclear Polarization in Double Quantum Dots

et al. 2012

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We use electric dipole spin resonance to measure dynamic nuclear polarization in InAs nanowire quantum dots. The resonance shifts in frequency when the system transitions between metastable high and low current states, indicating the presence of nuclear polarization. We propose that the low and the high current states correspond to different total Zeeman energy gradients between the two quantum dots. In the low current state, dynamic nuclear polarization efficiently compensates the Zeeman gradient due to the g-factor mismatch, resulting in a suppressed total Zeeman gradient.We present a theoretical model of electron-nuclear feedback that demonstrates a fixed point in nuclear polarization for nearly equal Zeeman splittings in the two dots and predicts a narrowed hyperfine gradient distribution.

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Detection of spin injection into a double quantum dot: Violation of magnetic-field-inversion symmetry of nuclear polarization instabilities

Cited by 4 publications

References 27 publications

Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime

Temperature-dependent dynamical nuclear polarization bistabilities in double quantum dots in the spin-blockade regime

Sensing Kondo correlations in a suspended carbon nanotube mechanical resonator with spin‐orbit coupling

Suppression of Zeeman Gradients by Nuclear Polarization in Double Quantum Dots

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