Tuning across the BCS-BEC crossover in the multiband superconductor Fe 1+ y Se x Te 1− x : An angle-resolved photoemission study
| Autor: | Mohit Randeria, Shahar Rinott, E. D. L. Rienks, Amina Taleb-Ibrahimi, Amit Kanigel, K. B. Chashka, Patrick Le Fèvre, François Bertran, Amit Ribak |
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| Rok vydání: | 2017 |
| Předmět: |
Condensed Matter::Quantum Gases
Physics Superconductivity Multidisciplinary Condensed matter physics Condensed Matter::Other Photoemission spectroscopy Crossover Fermi energy Context (language use) Angle-resolved photoemission spectroscopy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Ultracold atom Condensed Matter::Superconductivity Pairing 0103 physical sciences Condensed Matter::Strongly Correlated Electrons Atomic physics 010306 general physics 0210 nano-technology |
| Zdroj: | Science Advances. 3 |
| ISSN: | 2375-2548 |
| DOI: | 10.1126/sciadv.1602372 |
| Popis: | The crossover from Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose-Einstein condensation (BEC) is difficult to realize in quantum materials because, unlike in ultracold atoms, one cannot tune the pairing interaction. We realize the BCS-BEC crossover in a nearly compensated semimetal, Fe1+y Se x Te1-x , by tuning the Fermi energy eF via chemical doping, which permits us to systematically change Δ/eF from 0.16 to 0.50, where Δ is the superconducting (SC) gap. We use angle-resolved photoemission spectroscopy to measure the Fermi energy, the SC gap, and characteristic changes in the SC state electronic dispersion as the system evolves from a BCS to a BEC regime. Our results raise important questions about the crossover in multiband superconductors, which go beyond those addressed in the context of cold atoms. |
| Databáze: | OpenAIRE |
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