Abstract
Operation speed and coherence time are two core measures for the viability of a qubit. Strong spin-orbit interaction (SOI) and relatively weak hyperfine interaction make holes in germanium (Ge) intriguing candidates for spin qubits with rapid, all-electrical coherent control. Here we report ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire (GHW). Mediated by the strong SOI, a Rabi frequency exceeding 540 MHz is observed at a magnetic field of 100 mT, setting a record for ultrafast spin qubit control in semiconductor systems. We demonstrate that the strong SOI of heavy holes (HHs) in our GHW, characterized by a very short spin-orbit length of 1.5 nm, enables the rapid gate operations we accomplish. Our results demonstrate the potential of ultrafast coherent control of hole spin qubits to meet the requirement of DiVincenzo’s criteria for a scalable quantum information processor.
Highlights
Operation speed and coherence time are two core measures for the viability of a qubit
A scanning electron microscope (SEM) image of the double quantum dot (DQD) device is shown in Fig. 1a (Supplementary Fig. 1a shows a schematic of the device)
While PSB44 is usually detected in the (0,2) or (2,0) to (1,1) charge configurations, it has been observed in other charge configurations as well[45]
Summary
Operation speed and coherence time are two core measures for the viability of a qubit. The conventional approach of using magnetic fields to operate single-qubit gates results in relatively low Rabi frequencies[12], spurring the development of electrically driven spin resonance based on the spin–orbit interaction[15] as an alternative.
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