Quasiparticle dispersion of the t-J and Hubbard models

TL;DR

This study calculates the spectral weight of the t-J and Hubbard models using advanced numerical techniques, revealing key features of quasiparticle behavior relevant to understanding high-temperature superconductors.

Contribution

It provides detailed spectral weight calculations across various densities, supporting theories of cuprates based on hole behavior in antiferromagnetic backgrounds.

Findings

Identification of a low-energy quasiparticle peak with bandwidth ~J

Observation of a broad valence band peak at energies ~t

Persistence of spectral features away from half-filling

Abstract

The spectral weight ${\rm A({\bf p},\omega)}$ of the two dimensional ${\rm t-J}$ and Hubbard models has been calculated using exact diagonalization and quantum Monte Carlo techniques, at several densities ${\rm 1.0 \leq \langle n \rangle \leq 0.5}$. The photoemission $(\omega < 0)$ region contains two dominant distinct features, namely a low-energy quasiparticle peak with bandwidth of order J, and a broad valence band peak at energies of order t. This behavior $persists$ away from half-filling, as long as the antiferromagnetic (AF) correlations are robust. The results give support to theories of the copper oxide materials based on the behavior of holes in antiferromagnets, and it also provides theoretical guidance for the interpretation of experimental photoemission data for the cuprates.