We perform a fluctuation analysis of the pairing interaction in the hole-doped Hubbard model within the dynamical cluster approximation. Our analysis reveals that spin-fluctuation-mediated pairing differs qualitatively in the over- and underdoped regimes. In the underdoped regime, we show that the spin-fermion coupling exhibits a pronounced node–antinode dichotomy and mediates a strong attractive interaction between antinodal fermions. This explains why superconductivity persists at underdoping in the Hubbard model and cuprate materials, despite the lack of coherent quasiparticle excitations in the pseudogap regime.

Biography

Yang Yu recently received his Ph.D. from the University of Michigan under the supervision of Prof. Emanuel Gull. He will soon join Prof. Karsten Held’s group at the Vienna University of Technology as a postdoctoral researcher.

Inviter: Kun Chen