Hyperfine effects in a single hole GaAs/AlGaAs double quantum dot device

Hole spin qubits are attractive because, compared to electrons, they are predicted theoretically to have significantly weaker interactions with host nuclei, resulting in longer coherence times [1]. As a result it is more challenging to quantify hyperfine (hf) effects with holes. In Ref. [2], in a quantum point contact device, Dynamic Nuclear Polarization (DNP) through the hf interaction with holes was undetectable. In this work, we detect and explore small DNP effects in a single hole GaAs/AlGaAs gated DQD device using a modified EDSR technique [3]. As compared to our previous studies [3], the device is tuned to a much smaller inter-dot coupling regime to minimize spin-orbit effects and to make nuclear spin effects detectable.
[1] Philippopoulos, et al. PRB 100, 125402 (2019);
[2] Keane, et al., Nano Lett. 11, 3147 (2011);
[2] Studenikin et al., http://meetings.aps.org/Meeting/MAR19/Session/H35.13