Reducing disorder in PbTe nanowires for Majorana research

Topological quantum computing is based on the braiding of Majorana zero modes encoding topological qubits. A promising candidate platform for Majorana zero modes is semiconductor-superconductor hybrid nanowires. The realization of topological qubits and braiding operations requires scalable and disorder-free nanowire networks. Although the scalability of in-plane InAs and InSb nanowires, combined with the shadow-wall growth of superconductors, has been demonstrated, the discernible lattice mismatch at the nanowire-substrate interface introduces disorder, posing a significant hurdle to progress. In this work, we address this challenge by combining selective area and shadow-wall growth to fabricate PbTe-Pb hybrid nanowires—a promising Majorana system—on a nearly perfectly lattice-matched ‘substrate’, Pb_1-xEu_xTe. Transmission electron microscopy reveals an atomically sharp surface of the Pb_1-xEu_xTe and clean PbTe-Pb interface, indicating potential for creating a clean nanowire system to explore Majorana zero modes and advance topological quantum computing.