Autor: |
Rinott, S., Ribak, K. B. Chashka A., Taleb-Ibrahimi, E. D. L. Rienks A., Fevre, P. Le, Bertran, F., Randeria, M., Kanigel, A. |
Rok vydání: |
2017 |
Předmět: |
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Zdroj: |
Science Advances 3, e1602372 (2017) |
Druh dokumentu: |
Working Paper |
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 Fe$_{1+y}$Se$_x$Te$_{1-x}$ by tuning the Fermi energy, $\epsilon_F$, via chemical doping, which permits us to systematically change $\Delta / \epsilon_F$ from 0.16 to 0.5 were $\Delta$ 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: |
arXiv |
Externí odkaz: |
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