Magnetic Doublon Bound States in the Kondo Lattice Model

ORAL

Abstract

We present a novel pairing mechanism for electrons, mediated by magnons. These paired bound states are termed magnetic doublons. Applying numerically exact techniques (exact diagonalization and the density-matrix renormalization group, DMRG) to the Kondo lattice model at strong exchange coupling J for different fillings and magnetic configurations, we demonstrate that magnetic doublon excitations exist as composite objects with extremely weak dispersion at excitation energies of the order of 3J/2 above the ground state. They are highly stable, support a novel "inverse'' colossal magnetoresistance and potentially other effects like metastable superconductivity, or cooling via quantum distillation.

[1] Rausch, Potthoff, Kawakami arXiv:1909.11896

*R.R. would like to thank the Japan Society for the Promotion of Science (JSPS) and the Alexander von Humboldt Foundation.
Computations were partially performed at the Yukawa Institute for Theoretical Physics, Kyoto.
We gratefully acknowledge the support by the Deutsche Forschungsgemeinschaft within the SFB 925 (project B5), by the Cluster of Excellence Advanced Imaging of Matter EXC 2056 (project ID 390715994), as well as by JSPS KAKENHI (grant No. JP15H05855, JP18H01140, JP19H01838).

–

Presenters

  • Roman Rausch

    • University of Kyoto

Authors

  • Roman Rausch

    • University of Kyoto

  • Michael Potthoff

    • I. Institute for Theoretical Physics, University of Hamburg

  • Norio Kawakami

    • Department of Physics, Kyoto University
    • Physical Society of Japan
    • Kyoto University
    • University of Kyoto