Small Fermi surface in the one-dimensional Kondo lattice model

TL;DR

This paper uses DMRG to investigate the one-dimensional Kondo lattice model, revealing a small Fermi surface in many phases, and highlights how boundary conditions influence the interpretation of results.

Contribution

It demonstrates that open boundary conditions can significantly affect spin correlations, leading to a different understanding of the Fermi surface in the model.

Findings

Presence of a small Fermi surface in large parts of the phase diagram

Open boundary conditions induce charge perturbations affecting spin oscillations

Contrasts with previous studies that suggested a different Fermi surface size

Abstract

We study the one-dimensional Kondo lattice model through the density matrix renormalization group (DMRG). Our results for the spin correlation function indicate the presence of a small Fermi surface in large portions of the phase diagram, in contrast to some previous studies that used the same technique. We argue that the discrepancy is due to the open boundary conditions, which introduce strong charge perturbations that strongly affect the spin Friedel oscillations.