近日，英国曼彻斯特大学的A. K. Geim&Julien Barrier及其研究小组与浙江大学的Na Xin等人合作并取得一项新进展。经过不懈努力，他们揭示量子霍尔体系中的一维邻近超导性。相关研究成果已于2024年4月24日在国际权威学术期刊《自然》上发表。
该研究团队证实，在最小扭曲双层石墨烯中，畴壁在量子霍尔体系内能支持异常强大的邻近超导性，从而使得约瑟夫森结能够在邻近超导电极的上临界场中正常工作。他们发现，临界电流呈现非振荡特性，且在整个量子化场范围内几乎保持稳定，其数值受限于畴壁内弹道式、严格一维电子通道的量子电导。
该系统在量子化领域具有独一无二的能力，即支持Andreev束缚态，这为未来的深入探索提供了许多有趣的研究方向。
据悉，将超导性与量子霍尔效应相结合，实现了约瑟夫森结中超导电极间库珀对的输运，这一过程由一维边缘态介导。这种兴趣是由发现新物理学的前景所激发的，包括拓扑保护的准粒子，但也延伸到计量和器件应用。到目前为止，通过量子霍尔导体实现可探测的超电流被证明是具有挑战性的。
附：英文原文
Title: One-dimensional proximity superconductivity in the quantum Hall regime
Author: Barrier, Julien, Kim, Minsoo, Kumar, Roshan Krishna, Xin, Na, Kumaravadivel, P., Hague, Lee, Nguyen, E., Berdyugin, A. I., Moulsdale, Christian, Enaldiev, V. V., Prance, J. R., Koppens, F. H. L., Gorbachev, R. V., Watanabe, K., Taniguchi, T., Glazman, L. I., Grigorieva, I. V., Falko, V. I., Geim, A. K.
Issue&Volume: 2024-04-24
Abstract: 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. This interest has been motivated by prospects of finding new physics, including topologically protected quasiparticles, but also extends into metrology and device applications. So far it has proven challenging to achieve detectable supercurrents through quantum Hall conductors. Here we show 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 is 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. The system described is unique in its ability to support Andreev bound states at quantizing fields and offers many interesting directions for further exploration.
DOI: 10.1038/s41586-024-07271-w
