Quantum transport in in-plane selective area InSb-Al nanowire quantum networks

Strong spin-orbit semiconductor nanowires coupled to a superconductor are predicted to host Majorana zero modes. Exchange (braiding) operations of the Majorana modes form the logical gates of a topological quantum computer and require a network of nanowires. Here, we implement an in-plane selective-area growth technique for InSb-Al allowing complex semiconductor-superconductor nanowire networks with excellent quantum transport properties. Essential quantum transport phenomena for topological quantum computing are demonstrated in these structures including phase-coherent transport up to 5 harmonics of Aharonov-Bohm oscillations with a phase coherence length of ~10 μm. Tunneling spectroscopy on hybrid InSb-Al nanowires demonstrates a hard superconducting gap, accompanied by 2e-periodic Coulomb oscillations with an Al-based Cooper pair island integrated in the nanowire network. The results, together with possible Majorana signatures, confirm the high quality of the InSb nanowire networks, holding great promise for this platform for scalable topological networks.