https://doi.org/10.1007/s100510050891
Unusually flat hole dispersion relation in the two-dimensional Hubbard model and restoration of coherence by addition of pair-hopping processes
1
Institut für Theoretische Physik III, Universität Stuttgart, Pfaffenwaldring 57,
70550 Stuttgart, Germany
2
Institute for Solid State Physics, University of Tokyo, 7-22-1 Roppongi, Minato-ku,
Tokyo 106, Japan
Corresponding author: a assaad@theo3.physik.uni-stuttgart.de
Received:
22
March
1999
Published online: 15 August 1999
The dispersion relation of a doped hole in the half-filled
2D Hubbard model is shown to follow a |k|4
law around the 
and 
points in the Brillouin zone. Upon addition of pair-hopping
processes this dispersion relation is unstable
towards a 
law. The above follows from
T=0 Quantum Monte-Carlo calculations of the single particle
spectral function 
on 
lattices.
We discuss finite dopings and argue that the added term restores
coherence to charge dynamics and drives the system towards a
superconductor.
PACS: 71.10.Fd – Lattice fermion models (Hubbard model, etc.) / 71.30.+h – Metal-insulator transitions and other electronic transitions
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999
