Absence of a Magnetic Field Induced Metal-Insulator Transition in Kondo Insulators

TL;DR

This study shows that in one-dimensional Kondo insulators, a magnetic field does not induce a metal-insulator transition, challenging previous expectations and aligning with recent experimental observations.

Contribution

The paper provides a combined numerical and analytical analysis demonstrating the absence of a magnetic field induced transition in 1D Kondo insulators, extending the understanding of their behavior.

Findings

Quasiparticle gap remains finite at all magnetic fields.

No metal-insulator transition occurs in 1D Kondo insulators.

Results are consistent with recent experimental data.

Abstract

We investigate whether or not Kondo insulators undergo a magnetic field induced metal-insulator transition in one dimension at half filling using both a density matrix formulation of the numerical renormalization group and a new analytical approach. Contrary to expectations, the quasiparticle gap never vanishes at any field and no metal-insulator transition is found. We discuss generalizing our result to three dimensions and to the asymmetric Anderson lattice. Our result is consistent with recent experiments.