Tunneling spectroscopy of the spinon-Kondo effect in one-dimensional Mott insulators

TL;DR

This paper investigates the tunneling density of states in one-dimensional Mott insulators with boundary magnetic impurities, revealing universal power-law Fermi-edge singularities linked to the spinon-Kondo effect.

Contribution

It combines nonlinear Luttinger liquid theory and DMRG simulations to predict boundary Fermi-edge singularities in the TDOS of Mott insulators, highlighting the spinon-Kondo effect's universality.

Findings

Fermi-edge singularities appear at subgap energies near the boundary.

Resonances are asymmetric and follow a power-law form.

The power-law exponent is universal and determined by the spinon-Kondo effect.

Abstract

We study the tunneling density of states (TDOS) in one-dimensional Mott insulators at energies below the charge gap. By employing nonlinear Luttinger liquid theory and density-matrix renormalization group (DMRG) simulations, we predict that in the presence of a magnetic impurity at the boundary, characteristic Fermi-edge singularity features can appear at subgap energies in the TDOS near the boundary. In contrast to the Kondo effect in a metal, these resonances are strongly asymmetric and of power-law form. The power-law exponent is universal and determined by the spinon-Kondo effect.