Near-single-domain superconducting aluminium films on GaAs(111)A with remarkable crystalline quality for scalable quantum circuits
摘要
The realization of highly coherent and scalable superconducting quantum circuits relies critically on the structural perfection of epitaxial aluminium (Al) films. However, the presence of twin boundaries in these materials introduces prominent decoherence channels that severely limit device performance. Here, we have reproducibly grown near-single-domain superconducting Al films on GaAs(111)A wafers using molecular beam epitaxy. Synchrotron X-ray diffraction revealed twin-domain ratios of 0.00005 and 0.0003 for 19.4-nm- and 9.6-nm-thick films, respectively—the lowest reported for Al on any substrate and long considered unattainable for practical device platforms. Azimuthal scans across off-normal Al{