Pairing and non-Fermi liquid behavior in partially flat-band systems: Beyond nesting physics

  title={Pairing and non-Fermi liquid behavior in partially flat-band systems: Beyond nesting physics},
  author={Sharareh Sayyad and Edwin W. Huang and Motoharu Kitatani and Mohammad-Sadegh Vaezi and Zohar Nussinov and Abolhassan Vaezi and Hideo Aoki},
  journal={Physical Review B},
While multiband systems are usually considered for flat-band physics, here we study one-band models that have flat portions in the dispersion to explore correlation effects in the 2D repulsive Hubbard model in an intermediate coupling regime. The FLEX+DMFT~(the dynamical mean-field theory combined with the fluctuation exchange approximation) is used to show that we have a crossover from ferromagnetic to antiferromagnetic spin fluctuations as the band filling is varied, which triggers a… 
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