Thermodynamic properties of the one-dimensional Kondo insulators studied by the density matrix renormalization group method

TL;DR

This study investigates the thermodynamic behavior of one-dimensional Kondo insulators using the density matrix renormalization group method, revealing crossover phenomena and energy scales related to quasiparticle and spin gaps.

Contribution

It applies the DMRG method to compute thermodynamic properties of the 1D Kondo lattice model, providing detailed insights into crossover behavior and energy scales at low temperatures.

Findings

Crossover from localized spins and conduction electrons to coupled degrees of freedom.

Charge and spin susceptibilities' low temperature energy scales match quasiparticle and spin gaps.

Results obtained down to T=0.1t for various exchange constants.

Abstract

Thermodynamic properties of the one-dimensional Kondo lattice model at half-filling are studied by the density matrix renormalization group method applied to the quantum transfer matrix. Spin susceptibility, charge susceptibility, and specific heat are calculated down to T=0.1t for various exchange constants. The obtained results clearly show crossover behavior from the high temperature regime of nearly independent localized spins and conduction electrons to the low temperature regime where the two degrees of freedom couple strongly. The low temperature energy scales of the charge and spin susceptibilities are determined and shown to be equal to the quasiparticle gap and the spin gap, respectively, for weak exchange couplings.