Hole Pockets in the Doped 2D Hubbard Model

TL;DR

This study uses quantum Monte Carlo simulations to identify hole pockets in the electronic structure of the doped 2D Hubbard model, aligning with experimental observations in cuprates and explaining previous numerical discrepancies.

Contribution

It provides the first detailed numerical evidence of hole pockets in the doped 2D Hubbard model, clarifying their appearance and properties.

Findings

Hole pockets appear at specific momenta upon doping.

Pocket depth peaks near 90% filling and increases at lower temperatures.

Results align with experimental data on cuprates.

Abstract

The electronic momentum distribution ${\rm n({\bf k})}$ of the two dimensional Hubbard model is studied for different values of the coupling ${\rm U/t}$, electronic density ${\rm \langle n \rangle}$, and temperature, using quantum Monte Carlo techniques. A detailed analysis of the data on $8\times 8$ clusters shows that features consistent with hole pockets at momenta ${\rm {\bf k}=(\pm {\pi\over{2}},\pm {\pi\over{2}})}$ appear as the system is doped away from half-filling. Our results are consistent with recent experimental data for the cuprates discussed by Aebi et al. (Phys. Rev. Lett. {\bf 72}, 2757 (1994)). In the range of couplings studied, the depth of the pockets is maximum at ${\rm \langle n \rangle \approx 0.9}$, and it increases with decreasing temperature. The apparent absence of hole pockets in previous numerical studies of this model is explained.