Preformed Cooper pairs in flat-band semimetals
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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2022-07-19
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en
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5
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1-5
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Physical Review B, Volume 106, issue 2
Abstract
We study conditions for the emergence of the preformed Cooper pairs in materials hosting flat bands. As a particular example, we consider a semimetal, with a pair of three-band crossing points at which a flat band intersects with a Dirac cone, and focus on the s-wave intervalley pairing channel. The nearly dispersionless nature of the flat band at strong attraction between electrons promotes local Cooper pair formation so that the system may be modeled as an array of superconducting grains. Due to dispersive bands, Andreev scattering between the grains gives rise to the global phase-coherent superconductivity at low temperatures. We develop a mean-field theory to calculate transition temperature between the preformed Cooper pair state and the phase-coherent state for different interaction strengths in the Cooper channel. The transition temperature between semimetal and preformed Cooper pair phases is proportional to the interaction constant, the dependence of the transition temperature to the phase-coherent state on the interaction constant is weaker.Description
Funding Information: The authors are thankful to Vladimir Zyuzin for critical discussions and to Pirinem School of Theoretical Physics for warm hospitality. This research was supported by the Academy of Finland (Project No. 308339) and in parts by the Academy of Finland Centre of Excellence program (Project No. 336810). Publisher Copyright: © 2022 American Physical Society.
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Zyuzin, A A & Zyuzin, A Y 2022, ' Preformed Cooper pairs in flat-band semimetals ', Physical Review B, vol. 106, no. 2, L020502, pp. 1-5 . https://doi.org/10.1103/PhysRevB.106.L020502