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Updated: Jul 16, 2026

Silicon Metal-oxide-semiconductor Quantum Dots for Single-electron Pumping
Published on: June 3, 2015
Coherent manipulation of coupled electron spins in semiconductor quantum dots
J R Petta1, A C Johnson, J M Taylor
1Department of Physics, Harvard University, Cambridge, MA 02138, USA.
Abstract:
We demonstrated coherent control of a quantum two-level system based on two-electron spin states in a double quantum dot, allowing state preparation, coherent manipulation, and projective readout. These techniques are based on rapid electrical control of the exchange interaction. Separating and later recombining a singlet spin state provided a measurement of the spin dephasing time, T2*, of approximately 10 nanoseconds, limited by hyperfine interactions with the gallium arsenide host nuclei. Rabi oscillations of two-electron spin states were demonstrated, and spin-echo pulse sequences were used to suppress hyperfine-induced dephasing. Using these quantum control techniques, a coherence time for two-electron spin states exceeding 1 microsecond was observed.
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