Current-voltage characteristics of semiconductor-coupled superconducting weak links with large electrode separations
| Autor: | K. C. Wong, M. Thomas, Herbert Kroemer, H.-R. Blank, Evelyn L. Hu |
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| Rok vydání: | 1998 |
| Předmět: |
Orders of magnitude (temperature)
Niobium FOS: Physical sciences chemistry.chemical_element 02 engineering and technology 01 natural sciences Andreev reflection Superconductivity (cond-mat.supr-con) Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences 010306 general physics Superconductivity Physics Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics business.industry Condensed Matter - Superconductivity Shot noise Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology Semiconductor chemistry Electrode 0210 nano-technology Fermi gas business |
| Zdroj: | Physical Review B. 58:11676-11684 |
| ISSN: | 1095-3795 0163-1829 |
| Popis: | We have studied the current-voltage characteristics of superconducting weak links in which the coupling medium is the 2-D electron gas in InAs-based semiconductor quantum wells, with relatively large (typically 0.5 micron) separations between niobium electrodes. The devices exhibit Josephson-like current-voltage characteristics; however, the falloff of the differential resistance with decreasing temperature is thermally activated, and is orders of magnitude slower than for more conventional weak links. Most unexpectedly, the thermal activation energies are found to be proportional to the width of the device, taken perpendicular to the current flow. This behavior falls outside the range of established theories; we propose that it is a fluctuation effect caused by giant shot noise associated with multiple Andreev reflections. The possibility of non-equilibrium effects is discussed. Comment: 10 pages, 6 figures, PDF format, submitted to PRB |
| Databáze: | OpenAIRE |
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