Tuning across the BCS-BEC crossover in the multiband superconductor Fe
| Autor: | Shahar, Rinott, K B, Chashka, Amit, Ribak, Emile D L, Rienks, Amina, Taleb-Ibrahimi, Patrick, Le Fevre, François, Bertran, Mohit, Randeria, Amit, Kanigel |
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| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Science Advances |
| ISSN: | 2375-2548 |
| Popis: | A BCS-BEC crossover in a multiband superconductor has been observed experimentally using ARPES. 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+ySexTe1−x, by tuning the Fermi energy εF via chemical doping, which permits us to systematically change Δ/εF 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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