The realization of a topological qubit calls for advanced techniques to readily and reproducibly engineer induced superconductivity in semiconductor nanowires. Here, we introduce an on-chip fabrication paradigm based on shadow walls that offers substantial advances in device quality and reproducibility. It allows for the implementation of novel quantum devices and ultimately topological qubits while eliminating many fabrication steps such as lithography and etching. This is critical to preserve the integrity and homogeneity of the fragile hybrid interfaces. The approach simplifies the reproducible fabrication of devices with a hard induced superconducting gap and ballistic normal-/superconductor junctions. Large gate-tunable supercurrents and high-order multiple Andreev reflections manifest the exceptional coherence of the resulting nanowire Josephson junctions. Our approach enables, in particular, the realization of 3-terminal devices, where zero-bias conductance peaks emerge in a magnetic field concurrently at both boundaries of the one-dimensional hybrids.
@article{arxiv.2007.14383,
title = {Shadow-wall lithography of ballistic superconductor-semiconductor quantum devices},
author = {Sebastian Heedt and Marina Quintero-Pérez and Francesco Borsoi and Alexandra Fursina and Nick van Loo and Grzegorz P. Mazur and Michał P. Nowak and Mark Ammerlaan and Kongyi Li and Svetlana Korneychuk and Jie Shen and May An Y. van de Poll and Ghada Badawy and Sasa Gazibegovic and Kevin van Hoogdalem and Erik P. A. M. Bakkers and Leo P. Kouwenhoven},
journal= {arXiv preprint arXiv:2007.14383},
year = {2021}
}