Transparent Josephson junctions in higher-order topological insulator WTe2 via Pd diffusion

作     者：Martin Endres Artem Kononov Michael Stiefel Marcus Wyss Hasitha Suriya Arachchige Jiaqiang Yan David Mandrus Kenji Watanabe Takashi Taniguchi Christian Schönenberger 

作者机构：Department of Physics University of Basel Klingelbergstrasse 82 4056 Basel Switzerland Laboratory for Nanoscale Material Science Swiss Federal Laboratories for Material Science and Technology EMPA Überlandstrasse 129 8600 Dübendorf Switzerland Swiss Nanoscience Institute University of Basel Klingelbergstrasse 82 4056 Basel Switzerland Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996 USA Material Science and Technology Division Oak Ridge Laboratory Oak Ridge Tennessee 37831 USA Department of Materials Science and Engineering University of Tennessee Knoxville Tennessee 37996 USA National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan 

出 版 物：《Physical Review Materials》 (Physic. Rev. Mat.)

年 卷 期：2022年第6卷第8期

页      面：L081201-L081201页

核心收录：

基　　金：Basic Energy Sciences, BES Division of Materials Sciences and Engineering, DMSE QSIT U.S. Department of Energy, USDOE Shull Wollan Center National Center of Competence in Research Quantum Science and Technology, NCCR QSIT Office of Science, SC Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, SNF Japan Science and Technology Agency, JST Georg H. Endress Foundation European Research Council, ERC Swiss Nanoscience Institute, SNI Horizon 2020 Ministry of Education, Culture, Sports, Science and Technology, MEXT Horizon 2020 Framework Programme, H2020, (787414) Horizon 2020 Framework Programme, H2020 Gordon and Betty Moore Foundation, GBMF, (GBMF9069) Gordon and Betty Moore Foundation, GBMF Core Research for Evolutional Science and Technology, CREST, (JPMJCR15F3) Core Research for Evolutional Science and Technology, CREST 

主　　题：Josephson effect Proximity effect Superconductivity Surface diffusion Topological insulators Van der Waals systems 

摘      要：Highly transparent superconducting contacts to a topological insulator (TI) remain a persistent challenge on the route to engineer topological superconductivity. Recently, the higher-order TI WTe2 was shown to turn superconducting when placed on palladium (Pd) bottom contacts, demonstrating a promising material system in pursuing this goal. Here, we report the diffusion of Pd into WTe2 and the formation of superconducting PdTex as the origin of observed superconductivity. We find an atomically sharp interface in the direction vertical to the van der Waals layers between the diffusion crystal and its host crystal, forming state-of-the-art superconducting contacts to a TI. The diffusion is discovered to be nonuniform along the width of the WTe2 crystal, with a greater extent along the edges compared to the bulk. The potential of this contacting method is highlighted in transport measurements on Josephson junctions by employing external superconducting leads.