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arXiv · 1607.07852

Spin-orbit signatures in the dynamics of singlet-triplet qubits in double quantum dots

Juan E. Rolon·Ernesto Cota·Sergio E. Ulloa
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Abstract

We characterize numerically and analytically the signatures of the spin-orbit interaction in a two-electron GaAs double quantum dot in the presence of an external magnetic field. In particular, we obtain the return probability of the singlet state by simulating Landau-Zener voltage detuning sweeps which traverse the singlet-triplet ($S-T_+$) resonance. Our results indicate that non-spin-conserving interdot tunneling processes arising from the spin-orbit interaction have well defined signatures. These allow direct access to the spin-orbit interaction scales and are characterized by a frequency shift and Fourier amplitude modulation of the Rabi flopping dynamics of the singlet-triplet qubits $S-T_0$ and $S-T_+$. By applying the Bloch-Feshbach projection formalism, we demonstrate analytically that the aforementioned effects originate from the interplay between spin-orbit interaction and processes driven by the hyperfine interaction between the electron spins and those of the GaAs nuclei.

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Juan E. Rolon, Ernesto Cota, Sergio E. Ulloa. 2016-07-26. Spin-orbit signatures in the dynamics of singlet-triplet qubits in double quantum dots. https://doi.org/10.1103/physrevb.95.195407

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