Jirovec, DanielIST Austria; Hofmann, Andrea CIST Austria; Ballabio, Andrea; Mutter, Philipp M.; Tavani, Giulio; Botifoll, Marc; Crippa, AlessandroIST Austria; Kukucka, JosipIST Austria; Sagi, OliverIST Austria; Martins, FredericoIST Austria; Saez Mollejo, JaimeIST Austria; Prieto Gonzalez, IvanIST Austria
Spin qubits are considered to be among the most promising candidates for building a quantum processor. Group IV hole spin qubits have moved into the focus of interest due to the ease of operation and compatibility with Si technology. In addition, Ge offers the option for monolithic superconductor-semiconductor integration. Here we demonstrate a hole spin qubit operating at fields below 10 mT, the critical field of Al, by exploiting the large out-of-plane hole g-factors in planar Ge and by encoding the qubit into the singlet-triplet states of a double quantum dot. We observe electrically controlled X and Z-rotations with tunable frequencies exceeding 100 MHz and dephasing times of 1μs which we extend beyond 15μs with echo techniques. These results show that Ge hole singlet triplet qubits outperform their electronic Si and GaAs based counterparts in speed and coherence, respectively. In addition, they are on par with Ge single spin qubits, but can be operated at much lower fields underlining their potential for on chip integration with superconducting technologies.
This research was supported by the Scientific Service Units of IST Austria through resources provided by the MIBA Machine Shop and the nanofabrication facility. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 844511, No. 75441, and by the FWF-P 30207 project. A.B. acknowledges support from the EU Horizon-2020 FET project microSPIRE, ID: 766955. M.B. and J.A. acknowledge funding from Generalitat de Catalunya 2017 SGR 327. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706) and is funded by the CERCA Programme / Generalitat de Catalunya. Part of the present work has been performed in the framework of Universitat Aut`onoma de Barcelona Materials Science PhD program. Part of the HAADFSTEM microscopy was conducted in the Laboratorio de Microscopias Avanzadas at Instituto de Nanociencia de Aragon-Universidad de Zaragoza. ICN2 acknowledge support from CSIC Research Platform on Quantum Technologies PTI-001. M.B. acknowledges funding from AGAUR Generalitat de Catalunya FI PhD grant.
Jirovec D, Hofmann AC, Ballabio A, et al. A singlet triplet hole spin qubit in planar Ge. arXiv.
Jirovec, D., Hofmann, A. C., Ballabio, A., Mutter, P. M., Tavani, G., Botifoll, M., … Katsaros, G. (n.d.). A singlet triplet hole spin qubit in planar Ge. arXiv.
Jirovec, Daniel, Andrea C Hofmann, Andrea Ballabio, Philipp M. Mutter, Giulio Tavani, Marc Botifoll, Alessandro Crippa, et al. “A Singlet Triplet Hole Spin Qubit in Planar Ge.” ArXiv, n.d.
D. Jirovec et al., “A singlet triplet hole spin qubit in planar Ge,” arXiv. .
Jirovec D, Hofmann AC, Ballabio A, Mutter PM, Tavani G, Botifoll M, Crippa A, Kukucka J, Sagi O, Martins F, Saez Mollejo J, Prieto Gonzalez I, Borovkov M, Arbiol J, Chrastina D, Isella G, Katsaros G. A singlet triplet hole spin qubit in planar Ge. arXiv, 2011.13755.
Jirovec, Daniel, et al. “A Singlet Triplet Hole Spin Qubit in Planar Ge.” ArXiv, 2011.13755.