Measurement of Temporal Correlations of the Overhauser Field in a Double Quantum Dot

作者：Reilly D J^*; Taylor J M; Laird E A; Petta J R; Marcus C M; Hanson M P; Gossard A C

来源：Physical Review Letters, 2008, 101(23): 236803.

DOI：10.1103/PhysRevLett.101.236803

In quantum dots made from materials with nonzero nuclear spins, hyperfine coupling creates a fluctuating effective Zeeman field (Overhauser field) felt by electrons, which can be a dominant source of spin qubit decoherence. We characterize the spectral properties of the fluctuating Overhauser field in a GaAs double quantum dot by measuring correlation functions and power spectra of the rate of singlet-triplet mixing of two separated electrons. Away from zero field, spectral weight is concentrated below 10 Hz, with similar to 1/f(2) dependence on frequency f. This is consistent with a model of nuclear spin diffusion, and indicates that decoherence can be largely suppressed by echo techniques.

• 出版日期2008-12-5