Bistability of the Nuclear Polarisation created through optical pumping in InGaAs Quantum Dots
Bistability of the Nuclear Polarisation created through optical pumping in InGaAs Quantum Dots
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InGaAs 量子点中光泵浦产生的核极化的双稳定性
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
P. Voisin
中科院分区：
文献类型：
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作者：
P. Braun;B. Urbaszek;T. Amand;X. Marie;O. Krebs;B. Eble;A. Lemaître;P. Voisin
We show that optical pumping of electron spins in individual $\mathrm{InGaAs}$ quantum dots leads to strong nuclear polarization that we measure via the Overhauser shift ${\ensuremath{\delta}}_{n}$ in magnetophotoluminescence experiments between 0 and $4\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. We find a strongly nonmonotonous dependence of ${\ensuremath{\delta}}_{n}$ on the applied magnetic field, with a maximum nuclear polarization of about 40% for intermediate magnetic fields. We observe that ${\ensuremath{\delta}}_{n}$ is larger for nuclear fields antiparallel to the external field than in the parallel configuration. A bistability in the dependence of ${\ensuremath{\delta}}_{n}$ on the spin polarization of the optically injected electrons is found. All our findings are qualitatively understood with a model based on a simple perturbative approach.
We show that optical pumping of electron spins in individual $\mathrm{InGaAs}$ quantum dots leads to strong nuclear polarization that we measure via the Overhauser shift ${\ensuremath{\delta}}_{n}$ in magnetophotoluminescence experiments between 0 and $4\phantom{\rule{0.3em}{0ex}}\mathrm{T}$. We find a strongly nonmonotonous dependence of ${\ensuremath{\delta}}_{n}$ on the applied magnetic field, with a maximum nuclear polarization of about 40% for intermediate magnetic fields. We observe that ${\ensuremath{\delta}}_{n}$ is larger for nuclear fields antiparallel to the external field than in the parallel configuration. A bistability in the dependence of ${\ensuremath{\delta}}_{n}$ on the spin polarization of the optically injected electrons is found. All our findings are qualitatively understood with a model based on a simple perturbative approach.