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 A (k,ω), the Fermi surface, the momentum distribution function n (k), the dispersion, and the density of states N (ω) in the intermediate-coupling regime (U=8) at low temperatures (T=0.01-0.02). At high doping (n=0.7), the system resembles an ordinary weakly interacting metal. At low doping (n=0.92), 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- Tc cuprates superconductors. © 2007 The American Physical Society.
Underdoped cuprate phenomenology in the two-dimensional Hubbard model within the composite operator method
AVELLA, Adolfo;
2007
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 A (k,ω), the Fermi surface, the momentum distribution function n (k), the dispersion, and the density of states N (ω) in the intermediate-coupling regime (U=8) at low temperatures (T=0.01-0.02). At high doping (n=0.7), the system resembles an ordinary weakly interacting metal. At low doping (n=0.92), 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- Tc cuprates superconductors. © 2007 The American Physical Society.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
