Finite temperature properties of the 2D Kondo lattice model

TL;DR

This study investigates the finite-temperature behavior of the 2D Kondo lattice model using Lanczos techniques, revealing multiple energy scales, quasiparticle gaps, and heavy quasiparticles at various fillings and couplings.

Contribution

It provides new insights into the temperature-dependent properties and energy scales of the 2D Kondo lattice model, including quasiparticle gaps and heavy quasiparticles.

Findings

Quasiparticle gap scales linearly with Kondo coupling at half filling.

Two different temperature scales are identified from spin susceptibility.

Heavy quasiparticles are observed at finite doping.

Abstract

Using recently developed Lanczos technique we study finite-temperature properties of the 2D Kondo lattice model at various fillings of the conduction band. At half filling the quasiparticle gap governs physical properties of the chemical potential and the charge susceptibility at small temperatures. In the intermediate coupling regime quasiparticle gap scales approximately linearly with Kondo coupling. Temperature dependence of the spin susceptibility reveals the existence of two different temperature scales. A spin gap in the intermediate regime leads to exponential drop of the spin susceptibility at low temperatures. Unusual scaling of spin susceptibility is found for temperatures above 0.6 J. Charge susceptibility at finite doping reveals existence of heavy quasiparticles. A new low energy scale is found at finite doping.