"Decrease of d-wave pairing strength in spite of the persistence of magnetic excitations in the overdoped Hubbard model"

Edwin W. Huang: Douglas J. Scalapino, Thomas A. Maier, Brian Moritz, and Thomas P. Devereaux; Physical Review B , 07/17/17.

Additional Authors: Douglas J. Scalapino, Thomas A. Maier, Brian Moritz, and Thomas P. Devereaux

Abstract:

 

Evidence for the presence of high-energy magnetic excitations in overdoped La2SrCuO4  (LSCO) has raised questions regarding the role of spin fluctuations in the pairing mechanism. If they remain present in overdoped LSCO, why does Tc decrease in this doping regime? Here, using results for the dynamic spin susceptibility Imχ(q,ω) obtained from a determinantal quantum Monte Carlo calculation for the Hubbard model, we address this question. We find that while high-energy magnetic excitations persist in the overdoped regime, they lack the momentum to scatter pairs between the antinodal regions. It is the decrease in the spectral weight at large momentum transfer, not observed by resonant inelastic x-ray scattering, which leads to a reduction in the d-wave spin-fluctuation pairing strength.