Resonant pair-exchange scattering and BCS-BEC crossover in a system composed of dispersive and heavy incipient bands: A Feshbach analogy
We theoretically show that a two-band system with very different masses harbors a resonant pair scattering that leads to novel pairing properties, as highlighted by the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) crossover. Most importantly, the interband pair-exchange coupli...
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Published in | Physical review research Vol. 4; no. 1; p. 013032 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
American Physical Society
13.01.2022
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Online Access | Get full text |
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Summary: | We theoretically show that a two-band system with very different masses harbors a resonant pair scattering that leads to novel pairing properties, as highlighted by the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation (BEC) crossover. Most importantly, the interband pair-exchange coupling induces an effective intraband attraction in each band, enhancing the superfluidity/superconductivity. The effect, a kind of Suhl-Kondo mechanism, is specifically enhanced when the second band has a heavy mass and is incipient (lying close to, but just above, the chemical potential μ), which we call a resonant pair scattering. By elucidating the dependence of the effective interactions and gap functions on μ, we can draw an analogy between the resonant pair scattering and the Feshbach resonance. |
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ISSN: | 2643-1564 2643-1564 |
DOI: | 10.1103/PhysRevResearch.4.013032 |