Extremely Correlated Fermi Liquids: Self consistent solution of the second order theory

TL;DR

This paper develops a detailed microscopic theory for extremely correlated Fermi liquids in the t-J model, providing numerical results that match experimental features like spectral asymmetry and high energy kinks in cuprates.

Contribution

It introduces a self-consistent second order theoretical framework for extremely correlated Fermi liquids, validated against experimental observations in cuprate superconductors.

Findings

Asymmetric spectral line shapes observed in experiments are reproduced.

High energy kink features are explained and their dependence on band parameters analyzed.

The theory is valid in the overdoped regime for particle densities 0<n<0.75.

Abstract

We present detailed results from a recent microscopic theory of extremely correlated Fermi liquids, applied to the t-J model in two dimensions. We use typical sets of band parameters relevant to the cuprate superconductors. The second order theory in the parameter \lambda is argued to be quantitatively valid in the overdoped regime for 0 < n < 0.75 (n is the particle density). The calculation involves the self consistent solution of equations for an auxiliary Fermi liquid type Greens function and an adaptive spectral weight, or caparison factor, described in recent papers by Shastry (Refs. (1) and (5)). We present the numerical results at low as well as high T at various low to intermediate densities in the normal phase with emphasis placed on features that are experimentally accessible. We display the momentum space occupation function m(k), various energy dispersions locating the peaks of spectral functions, the optical conductivity, relaxation rates for quasiparticles, and the electronic spectral functions along various directions in the Brillouin zone, and with typical additional elastic scattering. The line-shapes have an asymmetric shape and a broad background that is seen in experiments near and beyond optimal hole doping, and validate approximate recent recent versions of the theory. The results display features such as the high energy kink, and provide an in depth understanding of its origin and dependence on band parameters.