Doped Kondo chain, a heavy Luttinger liquid

TL;DR

This paper investigates a one-dimensional doped Kondo lattice model, revealing a Heavy Tomonaga-Luttinger Liquid phase with divergent correlations and hybridization gaps, highlighting the effects of RKKY interactions on effective mass.

Contribution

It provides the first detailed DMRG analysis of the doped 1D SU(2) Kondo lattice, identifying heavy Luttinger liquid behavior and comparing with large-N mean field theories.

Findings

Divergent charge and spin correlations at the large Fermi surface.

Evidence of a hybridization gap at the small Fermi surface.

RKKY interactions significantly influence effective mass generation.

Abstract

The one dimensional $SU(2)$ Kondo Lattice model is studied by Density Matrix Renormalization Group away from half-filling. We find signatures of a Heavy Tomonaga-Luttinger Liquid (HTLL) phase, which describes one dimensional Heavy Fermions. We compute the wave-vector dependent charge and spin susceptibilities. Our results establish divergent charge and spin correlations at the large Fermi surface $k_F+\pi/2$, and its harmonics. We also find a signature of the hybridization gap at the small Fermi surface. We compare our $N\!=\!2$ results to the large-$N$ Slave Bosons mean field theory of the $SU(N)$ Kondo Lattice model, and find crucial effects of the RKKY interactions on the generation of renormalized effective mass for the $N\!=\!2$ model.