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Published on: October 13, 2017
Dynamics of quantum dot nuclear spin polarization controlled by a single electron
P Maletinsky1, A Badolato, A Imamoglu
1Institute of Quantum Electronics, ETH-Hönggerberg, CH-8093, Zürich, Switzerland. patrickm@phys.ethz.ch
Physical Review Letters
|October 13, 2007
Summary
Nuclear spin polarization in semiconductor quantum dots builds up in milliseconds. An electron rapidly depolarizes nuclei, but in its absence, spin lifetime extends to seconds, further enhanced by magnetic fields.
Area of Science:
- Quantum physics
- Condensed matter physics
- Materials science
Background:
- Nuclear spin polarization is crucial for quantum information processing.
- Understanding spin dynamics in semiconductor quantum dots is key to developing quantum technologies.
Purpose of the Study:
- To measure the buildup and decay dynamics of nuclear spin polarization in a single semiconductor quantum dot.
- To investigate the influence of external parameters, specifically the presence of a single electron, on nuclear spin lifetime.
Main Methods:
- Utilized a single semiconductor quantum dot system.
- Performed measurements of nuclear spin polarization buildup and decay.
- Varied external parameters, including the presence/absence of a single electron and applied magnetic fields.
Main Results:
- Achieved nuclear spin polarization in milliseconds.
- Demonstrated that a single electron significantly accelerates nuclear spin depolarization (milliseconds).
- Observed extended nuclear spin lifetimes (seconds) in the absence of an electron.
- Showed a 1-2 order of magnitude enhancement in nuclear spin lifetime by quenching dipole-dipole interactions with a 1 mT magnetic field.
Conclusions:
- Nuclear spin dynamics in quantum dots are highly sensitive to the electronic environment.
- Long nuclear spin lifetimes, essential for quantum memory, can be achieved by isolating nuclei from electrons and minimizing interactions.
- The findings provide a pathway for improving coherence times in quantum dot-based quantum information applications.
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