University of Minnesota
School of Physics & Astronomy
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Ke Wang

Charge Relaxation in a Single-electron Si/SiGe Double Quantum Dot
K. Wang, C. Payette, Y. Dovzhenko, P. W. Deelman J. R. Petta, Phys. Rev. Lett. 111, 046801 (2013)

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We measure the interdot charge relaxation time T_1 of a single electron trapped in an accumulation mode Si/SiGe double quantum dot. The energy level structure of the charge qubit is determined using photon assisted tunneling, which reveals the presence of a low lying excited state. We systematically measure T_1 as a function of detuning and interdot tunnel coupling and show that it is tunable over four orders of magnitude, with a maximum of 45 microseconds for our device configuration. Measured relaxation times are consistent with a phonon mediated energy relaxation process and indicate that low lying excited states may have important implications in the development of silicon spin qubits.