Strongly Enhanced Superconductivity Due to Finite Energy Spin Fluctuations Induced by an Incipient Band: A FLEX Study on the Bilayer Hubbard Model with Vertical and Diagonal Interlayer Hoppings
作者: Karin MatsumotoDaisuke OguraKazuhiko Kuroki
刊名: Journal of the Physical Society of Japan, 2020, Vol.89 (4)
来源数据库: The physical Society of Japan
DOI: 10.7566/JPSJ.89.044709
原始语种摘要: We study the spin-fluctuation-mediated s ±-wave superconductivity in the bilayer Hubbard model with vertical and diagonal interlayer hoppings. As in the two-leg ladder model with diagonal hoppings, studied previously by the present authors, superconductivity is strongly enhanced when one of the bands lies just below (or touches) the Fermi level, that is, when the band is incipient. The strong enhancement of superconductivity is because large weight of the spin fluctuations lies in an appropriate energy range, whereas the low energy, pair-breaking spin fluctuations are suppressed. The optimized eigenvalue of the linearized Eliashberg equation, a measure for the strength of superconductivity, is not strongly affected by the bare width of the incipient band, but the parameter regime where...
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  • Hubbard squash<美>[植]笋瓜
  • incipient 初期
  • narrow 狭窄的
  • strongly 强烈地
  • coexistence 共存
  • diagonal 对角线
  • FLEX 灵活的
  • regime 状况
  • bands 同心带
  • suppressed 被抑制的