Abstract
The two-dimensional Hubbard model is studied within the composite operator method (COM) with the self-energy computed in the self-consistent Born approximation (SCBA). The COM describes interacting electrons in terms of the new elementary excitations that appear in the system owing to strong correlations; residual interactions among these excitations are treated within the SCBA. On decreasing the doping (from the overdoped to underdoped region), anomalous features develop in the spectral function , the Fermi surface, the momentum distribution function , the dispersion, and the density of states in the intermediate-coupling regime at low temperatures . At high doping , the system resembles an ordinary weakly interacting metal. At low doping , a pseudogap opens, hot and cold spots appear, and non-Fermi-liquid features develop. This behavior, together with the presence of kinks in the calculated electronic dispersion, is in agreement with angle-resolved photoemission spectroscopy data for high- cuprates superconductors.
- Received 26 July 2006
DOI:https://doi.org/10.1103/PhysRevB.75.134518
©2007 American Physical Society