Hard Superconducting Gap and Diffusion-Induced Superconductors in Ge-Si Nanowires
| Autor: | Ang Li, Marcel A. Verheijen, Joost Ridderbos, Folkert K. de Vries, Matthias Brauns, Erik P. A. M. Bakkers, Jie Shen, Sebastian Kölling, Floris A. Zwanenburg, Wilfred G. van der Wiel, Alexander Brinkman |
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| Přispěvatelé: | Semiconductor Nanostructures and Impurities, Plasma & Materials Processing, Advanced Nanomaterials & Devices, Center for Quantum Materials and Technology Eindhoven, Atomic scale processing, Interfaces and Correlated Electron Systems |
| Rok vydání: | 2019 |
| Předmět: |
Josephson effect
Materials science Letter Majorana quasiparticle Nanowire UT-Hybrid-D chemistry.chemical_element FOS: Physical sciences Bioengineering Germanium 02 engineering and technology Ge−Si nanowire Condensed Matter::Materials Science hard superconducting gap Condensed Matter::Superconductivity Josephson junction Mesoscale and Nanoscale Physics (cond-mat.mes-hall) General Materials Science Critical field Quantum tunnelling Superconductivity Quantum Physics Condensed matter physics Condensed Matter - Mesoscale and Nanoscale Physics Mechanical Engineering Supercurrent topological superconductivity General Chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Magnetic field chemistry Superconductor−semiconductor hybrid device 0210 nano-technology Quantum Physics (quant-ph) |
| Zdroj: | Nano Letters Nano Letters, 20(1), 122-130. American Chemical Society Nano Letters: a journal dedicated to nanoscience and nanotechnology, 20(1) Nano letters, 20(1), 122-130. American Chemical Society |
| ISSN: | 1530-6992 1530-6984 |
| Popis: | We show a hard induced superconducting gap in a Ge-Si nanowire Josephson transistor up to in-plane magnetic fields of $250$ mT, an important step towards creating and detecting Majorana zero modes in this system. A hard induced gap requires a highly homogeneous tunneling heterointerface between the superconducting contacts and the semiconducting nanowire. This is realized by annealing devices at $180$ $^\circ$C during which aluminium inter-diffuses and replaces the germanium in a section of the nanowire. Next to Al, we find a superconductor with lower critical temperature ($T_\mathrm{C}=0.9$ K) and a higher critical field ($B_\mathrm{C}=0.9-1.2$ T). We can therefore selectively switch either superconductor to the normal state by tuning the temperature and the magnetic field and observe that the additional superconductor induces a proximity supercurrent in the semiconducting part of the nanowire even when the Al is in the normal state. In another device where the diffusion of Al rendered the nanowire completely metallic, a superconductor with a much higher critical temperature ($T_\mathrm{C}=2.9$ K) and critical field ($B_\mathrm{C}=3.4$ T) is found. The small size of diffusion-induced superconductors inside nanowires may be of special interest for applications requiring high magnetic fields in arbitrary direction. |
| Databáze: | OpenAIRE |
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