Interplay between the charge density wave phase and a pseudogap under antiferromagnetic correlations

Abstract

In this study, we explore the impact of short-range antiferromagnetic correlations on the charge density wave (CDW) phase in strongly correlated electron systems exhibiting the pseudogap phenomenon. Our investigation employs an n-pole approximation to consider the repulsive Coulomb interaction (U) and antiferromagnetic correlations. Considering an one-band Hubbard model to account for the Coulomb interaction and a BCS-like model for the CDW order parameter, we observed that an increase in U enhances antiferromagnetic fluctuations, resulting in a flattened re-normalized band around the antinodal point $(\pi ,0)$. The pseudogap manifests itself in the band structure and density of states, prompting exploration of various U and occupation number values. Our findings indicate that antiferromagnetic correlations significantly influence the CDW state, as the Fermi surface is reconstructed within the ordered phase. Furthermore, we found a Lifshitz transition inside both the CDW phase and the normal state, with the latter preceding the onset of the pseudogap.