Landau mapping and Fermi liquid parameters of the 2D t-J model

TL;DR

This study uses exact diagonalization to analyze the 2D t-J model, revealing it behaves as a Fermi liquid with a small Fermi surface and moderate quasiparticle attraction, based on Landau parameter analysis.

Contribution

It introduces a systematic decomposition of the momentum distribution function and establishes a Landau mapping to identify Fermi liquid behavior in the 2D t-J model.

Findings

2D t-J model exhibits Fermi liquid characteristics at small doping

Quasiparticle interactions are moderately attractive

Small Fermi surface confirmed by Landau parameters

Abstract

We study the momentum distribution function n(k) in the 2D t-J model on small clusters by exact diagonalization. We show that n(k) can be decomposed systematically into two components with Bosonic and Fermionic doping dependence. The Bosonic component originates from the incoherent motion of holes and has no significance for the low energy physics. For the Fermionic component we exlicitely perform the one-to-one Landau mapping between the low lying eigenstates of the t-J model clusters and those of an equivalent system of spin-1/2 quasiparticles. This mapping allows to extract the quasiparticle dispersion, statistics, and Landau parameters. The results show conclusively that the 2D t-J model for small doping is a Fermi liquid with a `small' Fermi surface and a moderately strong attractive interaction between the quasiparticles.