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

Rodrigo G. Pereira1, Bruno F. Marquez2, Karen Hallberg2,3, Tim Bauer4,5, and Reinhold Egger6

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Phys. Rev. B 113, 045402 – Published 2 January, 2026

DOI: https://doi.org/10.1103/wkmx-772j

Abstract

We study the tunneling density of states (TDOS) in one-dimensional (1D) 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.

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Phys. Rev. B 113, 045402– Published 2 January, 2026
  • Received 26 August 2025
  • Revised 15 October 2025
  • Accepted 12 December 2025
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