Abstract :
The temperature and doping dependence of the 2D Hubbard model is studied in the intermediate coupling regime (U=4). Strong 2D critical spin fluctuations dominating near half-filling are completely destroyed upon about 14% doping concentration, below which the imaginary part of the self-energy vanishes nearly quadratically in both frequency and temperature, a characteristic feature for the Fermi liquid. As the doping concentration is increased from half-filling, dynamical spin susceptibility shows a change from commensurate to incommensurate structure, leading to a three-peak structure in the spectral function in some region of the Brillouin zone.
