Charge sensing and controllable tunnel coupling in a Si/SiGe double quantum dot.

Simmons, C B; Thalakulam, Madhu; Rosemeyer, B M; Van Bael, B J; Sackmann, E K; Savage, D E; Lagally, M G; Joynt, R et al. · Nano Lett · 2009

basic_science · Level V

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Abstract

We report integrated charge sensing measurements on a Si/SiGe double quantum dot. The quantum dot is shown to be tunable from a single, large dot to a well-isolated double dot. Charge sensing measurements enable the extraction of the tunnel coupling t between the quantum dots as a function of the voltage on the top gates defining the device. Control of the voltage on a single such gate tunes the barrier separating the two dots. The measured tunnel coupling is an exponential function of the gate voltage. The ability to control t is an important step toward controlling spin qubits in silicon quantum dots.

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