One-electron spectral functions of the attractive Hubbard model at intermediate coupling

TL;DR

This paper analytically investigates the one-electron spectral function of the two-dimensional attractive-U Hubbard model at intermediate coupling, providing insights into its thermodynamic and transport properties relevant to high-temperature superconductors.

Contribution

It introduces an analytical approach using the self-consistent T-matrix approximation to study spectral functions and thermodynamics in the attractive Hubbard model at intermediate coupling.

Findings

Calculated the spectral function and self-energy analytically.

Analyzed the temperature dependence of chemical potential for bound pairs.

Compared theoretical results with experimental tunneling data in underdoped HTSC materials.

Abstract

We calculate the one-electron spectral function of the attractive-U Hubbard model in two dimensions. We work in the intermediate coupling and low density regime and evaluate analytically the self-energy. The results are obtained in a framework based on the self-consistent T-matrix approximation. We also calculate the chemical potential of the bound pairs as a function of temperature. On the basis of this calculation we analyze the low-temperature resistivity and specific heat in the normal state of this system. We compare our results with recent beautiful tunneling experiments in the underdoped regime of HTSC-materials.