Quasiparticle anisotropy and pseudogap formation from the weak-coupling renormalization group point of view

TL;DR

This paper investigates how quasiparticle properties and pseudogap formation in a 2D Hubbard model are influenced by weak interactions, revealing anisotropic behavior and vanishing quasiparticle weight near specific Fermi surface points.

Contribution

It provides a detailed analysis of quasiparticle anisotropy and pseudogap emergence using the one-loop functional renormalization group in the weak-coupling regime.

Findings

Quasiparticle weight vanishes near (pi,0) at van Hove filling.

Anisotropic pseudogap forms away from van Hove filling.

Spectral weight reduction occurs near hot spots and specific Fermi surface points.

Abstract

Using the one-loop functional renormalization group technique we evaluate the self-energy in the weak-coupling regime of the 2D t-t' Hubbard model. At van Hove (vH) band fillings and at low temperatures the quasiparticle weight along the Fermi surface (FS) continuously vanishes on approaching the (pi,0) point where the quasiparticle concept is invalid. Away from vH band fillings the quasiparticle peak is formed inside an anisotropic pseudogap and the self-energy has the conventional Fermi-liquid characteristics near the Fermi level. The spectral weight of the quasiparticle features is reduced on parts of the FS between the near vicinity of hot spots and the FS points closest to (pi,0) and (0,pi).