Nanowerk April 24, 2024
Extensive efforts have been undertaken to combine superconductivity and the quantum Hall effect so that Cooper-pair transport between superconducting electrodes in Josephson junctions is mediated by one-dimensional edge states. So far it has proven challenging to achieve detectable supercurrents through quantum Hall conductors. An international team of researchers (UK, South Korea, Spain, Japan, USA – Yale University) showed that domain walls in minimally twisted bilayer graphene support exceptionally robust proximity superconductivity in the quantum Hall regime, allowing Josephson junctions to operate in fields close to the upper critical field of superconducting electrodes. The critical current was found to be non-oscillatory and practically unchanging over the entire range of quantizing fields, with its value being limited by the quantum conductance of ballistic, strictly one-dimensional, electronic channels residing within the domain walls. According to the researchers the system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration… read more. TECHNICAL ARTICLE
Josephson junctions incorporating domain walls in MTGBs. Credit: Nature volume 628, pages741–745 (2024)