Underdoped cuprates phenomenology in the 2D Hubbard model within COM(SCBA)

TL;DR

This study uses the COM(SCBA) approach to analyze the 2D Hubbard model, revealing pseudogap formation and non-Fermi-liquid behavior in underdoped cuprates, consistent with experimental ARPES observations.

Contribution

It introduces a combined COM and SCBA methodology to analyze spectral and electronic properties of the 2D Hubbard model in the underdoped regime.

Findings

Identification of pseudogap opening at low doping

Observation of non-Fermi-liquid features

Detection of kinks in electronic dispersion

Abstract

The two-dimensional Hubbard model is studied within the Composite Operator Method (COM) with the residual self-energy computed in the Self-Consistent Born Approximation (SCBA). COM describes interacting electrons in terms of the new elementary excitations appearing in the system owing to strong correlations; residual interactions among these excitations are treated within the SCBA. The anomalous features appearing in the spectral function A(k,\omega), the momentum distribution function n(k) and the Fermi surface are analyzed for various values of the filling (from overdoped to underdoped region) in the intermediate coupling regime at low temperatures. For low doping, in contrast with the ordinary Fermi-liquid behavior of a weakly-correlated metal found at high doping, we report the opening of a pseudogap and some non-Fermi-liquid features as measured for cuprates superconductors. In addition, we show the presence of kinks in the calculated electronic dispersion in agreement with ARPES data.