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arXiv · 1008.0912

Nuclear Feedback in a Single Electron-Charged Quantum Dot under Pulsed Optical Control

Thaddeus D. Ladd·David Press·Kristiaan De Greve·Peter L. McMahon·Benedikt Friess·Christian Schneider·Martin Kamp·Sven Hoefling·Alfred Forchel·Yoshihisa Yamamoto
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Abstract

Electron spins in quantum dots under coherent control exhibit a number of novel feedback processes. Here, we present experimental and theoretical evidence of a feedback process between nuclear spins and a single electron spin in a single charged InAs quantum dot, controlled by the coherently modified probability of exciting a trion state. We present a mathematical model describing competition between optical nuclear pumping and nuclear spin-diffusion inside the quantum dot. The model correctly postdicts the observation of a hysteretic sawtooth pattern in the free-induction-decay of the single electron spin, hysteresis while scanning a narrowband laser through the quantum dot's optical resonance frequency, and non-sinusoidal fringes in the spin echo. Both the coherent electron-spin rotations, implemented with off-resonant ultrafast laser pulses, and the resonant narrow-band optical pumping for spin initialization interspersed between ultrafast pulses, play a role in the observed behavior. This effect allows dynamic tuning of the electron Larmor frequency to a value determined by the pulse timing, potentially allowing more complex coherent control operations.

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Thaddeus D. Ladd, David Press, Kristiaan De Greve, Peter L. McMahon, Benedikt Friess, Christian Schneider, Martin Kamp, Sven Hoefling, Alfred Forchel, Yoshihisa Yamamoto. 2010-12-15. Nuclear Feedback in a Single Electron-Charged Quantum Dot under Pulsed Optical Control. https://doi.org/10.1117/12.873978

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