Awesome news everyone! Our collaboration with the Katsaros group at ISTA, Granular aluminum induced superconductivity in germanium for hole spin-based hybrid devices, is now on the arxiv!!

Remember when we said our theory of proximitized super-holes opened many doors? Well, here is one of them. Superconductivity and spin polarization are competing effects, as magnetic fields tend to break Cooper pairs. This is a serious obstacle for hybrid devices such as Andreev spin qubits, especially when out-of-plane fields are required. In this work, granular aluminum comes to the rescue: by depositing this magnetic-field-resilient superconductor on Ge/SiGe heterostructures, a hard superconducting gap is induced in germanium that survives both in-plane and out-of-plane fields, allowing Zeeman splittings of Yu-Shiba-Rusinov states beyond 50 ueV (12 GHz). On top of the experimental demonstration, we reveal signatures of hole physics and discuss a driving mechanism for Andreev spin qubits that works regardless of the strength of the Rashba spin-orbit coupling. And guess what? The magnetotunnel term we recently introduced turned out to be quite important in this mechanism, showing once more that it packs a punch. Superconducting germanium is here to stay!