Single particle excitations of the Kondo lattice

TL;DR

This paper develops a simple theoretical framework for understanding single particle excitations in the Kondo lattice model, capturing key spectral features and their dependence on electron density.

Contribution

It introduces an effective Hamiltonian that describes coherent single particle fluctuations on a strong coupling background, aligning with numerical results.

Findings

Spectral function obeys Luttinger theorem including f-electrons

Reproduces variation of spectral function with density and parameters

Matches results from exact diagonalization and DMRG studies

Abstract

We present a simple theory for the description of the single particle excitations in the Kondo lattice model. Thereby we derive an `effective Hamiltonian' which describes the coherent propagation of single particle-like fluctuations on a strong coupling background. Even for f-electrons which are replaced by Kondo-spins, the resulting spectral function obeys the Luttinger theorem including the f-electrons, and our calculation fully reproduces the nontrivial variation of the spectral function and momentum distribution with electron density and parameter values as seen in exact diagonalization and density matrix renormalization group studies.