Dresden 2020 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 59: Correlated Electrons: Quantum Impurities and Kondo Physics; Other Materials

TT 59.2: Talk

Thursday, March 19, 2020, 15:15–15:30, HSZ 03

Magnetic doublon bound states in the Kondo Lattice Model — •Roman Rausch¹, Michael Potthoff², and Norio Kawakami¹ — ¹Kyoto University — ²University of Hamburg

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] R. Rausch, M. Potthoff, N. Kawakami, arXiv:1909.11896