Excitation Spectra in the 1-D Hubbard Model from Quantum-Monte-Carlo Simulations

1994 ◽  
pp. 113-124
Author(s):  
A. Muramatsu ◽  
R. Preuss ◽  
W. von der Linden ◽  
P. Dieterich ◽  
F. F. Assaad ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Excitation Spectra ◽  
Quantum Monte Carlo Simulations

QUANTUM MONTE CARLO SIMULATIONS FOR THE THREE-BAND HUBBARD MODEL

1992 ◽  
Vol 03 (01) ◽  
pp. 79-96 ◽  
Author(s):  
GEORG DOPF ◽  
ALEJANDRO MURAMATSU ◽  
WERNER HANKE
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Doping Concentration ◽  
Antiferromagnetic Order ◽  
Incommensurate Structure ◽  
Canonical Approach ◽  
Experimental Values ◽  
Quantum Monte Carlo Simulations

We present in this article results of Quantum Monte Carlo simulations for the three-band Hubbard model obtained both with the grand canonical approach as well as with the T =0 formalism. A direct comparison of Quantum Monte Carlo results with experimental values for the charge-transfer gap leads to a set of parameters for the three-band Hubbard model that consistently describes salient features of the high- T c superconductors. We find long-range antiferromagnetic order in the undoped case as well as an incommensurate structure for a doping concentration of δ≈0.20. Moreover the magnetic susceptibility as a function of doping δ is in a qualitative agreement with experiments. Concerning dynamical properties, we have evaluated the spectral density [Formula: see text]. The dispersion of the state with the lowest excitation energy is in very good agreement with experimental photoemission and inverse photoemission experiments for a doping concentration of δ=0.25. In the superconducting regime, we find that the interaction vertex for the pairing correlation function in the extended s-channel shows a maximum for δ~0.20, resembling the dependence of T c on doping. This feature is not present for other symmetries of the order parameter or in other parameter regions.

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