Selective area grown semiconductor-superconductor hybrids: a basis for topological networks

Research paper by S. Vaitiekėnas, A. M. Whiticar, M. T. Deng, F. Krizek, J. E. Sestoft, S. Marti-Sanchez, J. Arbiol, P. Krogstrup, L. Casparis, C. M. Marcus

Indexed on: 12 Feb '18Published on: 12 Feb '18Published in: arXiv - Physics - Mesoscopic Systems and Quantum Hall Effect


Majorana zero modes (MZMs) at the ends of one-dimensional topological superconductors are expected to exhibit non-Abelian braiding statistics, providing naturally fault-tolerant qubits. Complex networks for braiding, interference-based topological qubits and topological quantum computing architectures require either branched nanowires or two-dimensional hybrid heterostructures confined by etching and gating, each bringing challenges to scaling. Here, we demonstrate the viability of selective area grown (SAG) Al-InAs hybrid wires that can be patterned into structures with branches and loops, providing a new, flexible platform for topological superconducting networks. We find proximity-induced superconductivity with a hard induced gap and 2e-periodic Coulomb blockade, indicating strongly suppressed quasiparticle poisoning. The observed overshoot of Coulomb blockade peak spacing in a parallel magnetic field is consistent with interacting MZMs, with an amplitude consistent with previous experiments. We also measure electron phase-coherence length and spin-orbit coupling strength via interference measurements in an Aharonov-Bohm ring.