Ultrafast and Electrically Tunable Rabi Frequency in a Germanium Hut Wire Hole Spin Qubit.

Liu, He; Wang, Ke; Gao, Fei; Leng, Jin; Liu, Yang; Zhou, Yu-Chen; Cao, Gang; Wang, Ting et al. · Nano Lett · 2023

basic_science · Level V

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Abstract

Hole spin qubits based on germanium (Ge) have strong tunable spin-orbit interaction (SOI) and ultrafast qubit operation speed. Here we report that the Rabi frequency (<i>f</i><sub>Rabi</sub>) of a hole spin qubit in a Ge hut wire (HW) double quantum dot (DQD) is electrically tuned through the detuning energy (ϵ) and middle gate voltage (<i>V</i><sub>M</sub>). <i>f</i><sub>Rabi</sub> gradually decreases with increasing ϵ; on the contrary, <i>f</i><sub>Rabi</sub> is positively correlated with <i>V</i><sub>M</sub>. We attribute our results to the change of electric field on SOI and the contribution of the excited state in quantum dots to <i>f</i><sub>Rabi</sub>. We further demonstrate an ultrafast <i>f</i><sub>Rabi</sub> exceeding 1.2 GHz, which indicates the strong SOI in our device. The discovery of an ultrafast and electrically tunable <i>f</i><sub>Rabi</sub> in a hole spin qubit has potential applications in semiconductor quantum computing.