Effects of spin fluctuations in the t-J model

TL;DR

This paper investigates how spin fluctuations influence the electronic structure in the t-J model, using a selfenergy approach based on DMFT and perturbative corrections, revealing new bands and band deformations.

Contribution

It introduces a novel method combining DMFT with perturbative spin fluctuation effects to analyze the t-J model's electronic structure.

Findings

Identification of new quasiparticle bands due to spin fluctuations

Strong deformation of existing quasiparticle bands observed

Method effectively captures local correlations and spin effects

Abstract

Recent experiments on the Fermi surface and the electronic structure of the cuprate-supercondutors showed the importance of short range antiferromagnetic correlations for the physics in these systems. Theoretically, features like shadow bands were predicted and calculated mainly for the Hubbard model. In our approach we calculate an approximate selfenergy of the $t$-$J$ model. Solving the $U=\infty$ Hubbard model in the Dynamical Mean Field Theory (DMFT) yields a selfenergy that contains most of the local correlations as a starting point. Effects of the nearest neighbor spin interaction $J$ are then included in a heuristical manner. Formally like in $J$-perturbation theory all ring diagrams, with the single bubble assumed to be purely local, are summed to get a correction to the DMFT-self engergy This procedure causes new bands and can furnish strong deformation of quasiparticle bands. % Our results are finally compared with %former approaches to the Hubbard model.