Towards magnetic field resilience in transmon qubits using Sn-InAs nanowire junctions

Al/AlOx/Al Josephson junction based transmon qubits have achieved coherence times in the order of milliseconds. But the operation of these devices in magnetic field sensitive applications remains limited due to aluminum's low critical magnetic field and a superconducting gap of ∼180 µeV. In this work, we explore the magnetic field-resilience of voltage tunable transmon qubits based on Sn-InAs nanowire Josephson junctions integrated with NbTiN co-planar waveguides and interconnecting leads. Sn has a superconducting gap of ∼ 0.6 meV, while that of NbTiN is ∼ 2.25 meV. Sn-based hybrid Josephson junctions have demonstrated to have a larger induced superconducting gap compared to Al-based junctions. These properties make them a suitable candidate for investigating performance of qubits under applied magnetic fields and are expected to mitigate quasiparticle and vortex-induced losses.