Scherübl Zoltán, Fülöp Gergő, Moca Cătălin Paşcu, Gramich Jörg, Baumgartner Andreas, Makk Péter, Elalaily Tosson, Schönenberger Christian, Nygård Jesper, Zaránd Gergely, Csonka Szabolcs
Department of Physics, Budapest University of Technology and Economics and MTA-BME "Momentum" Nanoelectronics Research Group, H-1111, Budapest, Budafoki út 8., Hungary.
Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland.
Nat Commun. 2020 Apr 14;11(1):1834. doi: 10.1038/s41467-020-15322-9.
Various promising qubit concepts have been put forward recently based on engineered superconductor subgap states like Andreev bound states, Majorana zero modes or the Yu-Shiba-Rusinov (Shiba) states. The coupling of these subgap states via a superconductor strongly depends on their spatial extension and is an essential next step for future quantum technologies. Here we investigate the spatial extension of a Shiba state in a semiconductor quantum dot coupled to a superconductor. With detailed transport measurements and numerical renormalization group calculations we find a remarkable more than 50 nm extension of the zero energy Shiba state, much larger than the one observed in very recent scanning tunneling microscopy measurements. Moreover, we demonstrate that its spatial extension increases substantially in a magnetic field.
最近，基于诸如安德烈夫束缚态、马约拉纳零模或汤川-芝-拉西诺夫（芝）态等人工设计的超导体亚能隙态，人们提出了各种有前景的量子比特概念。这些亚能隙态通过超导体的耦合强烈依赖于它们的空间扩展，这是未来量子技术至关重要的下一步。在此，我们研究了耦合到超导体的半导体量子点中芝态的空间扩展。通过详细的输运测量和数值重整化群计算，我们发现零能芝态有显著超过50纳米的扩展，远大于最近扫描隧道显微镜测量中观察到的扩展。此外，我们证明其空间扩展在磁场中会大幅增加。
