Thermodynamics of doped Kondo insulator in one dimension: Finite Temperature DMRG Study

TL;DR

This study uses finite-temperature DMRG to explore the thermodynamics of a doped one-dimensional Kondo insulator, revealing crossover behaviors, spin gaps, and the transition to Tomonaga-Luttinger liquid states.

Contribution

It provides new insights into the finite-temperature properties and crossover phenomena of doped Kondo insulators in one dimension using advanced numerical methods.

Findings

Identification of two crossover temperatures near half filling.

Confirmation of Tomonaga-Luttinger liquid behavior at low temperatures.

Observation of the transition from metallic to insulating phase.

Abstract

The finite-temperature density-matrix renormalization-group method is applied to the one-dimensional Kondo lattice model near half filling to study its thermodynamics. The spin and charge susceptibilities and entropy are calculated down to T=0.03t. We find two crossover temperatures near half filling. The higher crossover temperature continuously connects to the spin gap at half filling, and the susceptibilities are suppressed around this temperature. At low temperatures, the susceptibilities increase again with decreasing temperature when doping is finite. We confirm that they finally approach to the values obtained in the Tomonaga-Luttinger (TL) liquid ground state for several parameters. The crossover temperature to the TL liquid is a new energy scale determined by gapless excitations of the TL liquid. The transition from the metallic phase to the insulating phase is accompanied by the vanishing of the lower crossover temperature.