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arXiv · 2605.16580

Revealing Hund superdispersion with tunneling spectroscopy

Luke C. Rhodes·Fabian B. Kugler·Olivier Gingras·Carolina Marques·Edgar Abarca Morales·Phil D. C. King·Antoine Georges·Peter Wahl
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Abstract

In cuprate superconductors, electron-electron repulsion results in characteristic spectroscopic features known as `waterfalls', where the sharp quasiparticle dispersion transitions into broad Hubbard bands. However, in multi-orbital systems, the additional Hund coupling results in behavior that defies the conventional Mott--Hubbard paradigm, creating qualitatively distinct `superdispersive' features in the spectral function. Here, we use tunneling spectroscopy to reveal this signature of Hund physics in Sr$_2$RuO$_4$. By combining density functional theory, dynamical mean-field theory, and continuum local density of states calculations, we show that the experimental features are in excellent agreement with theoretical predictions and intimately linked to the non-monotonous energy dependence of the real part of the self-energy in a Hund metal. Our results provide direct experimental evidence for Hund-induced spectroscopic features and open a new route to probing correlation effects in quantum materials.

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Luke C. Rhodes, Fabian B. Kugler, Olivier Gingras, Carolina Marques, Edgar Abarca Morales, Phil D. C. King, Antoine Georges, Peter Wahl. 2026-05-15. Revealing Hund superdispersion with tunneling spectroscopy. https://arxiv.org/abs/2605.16580

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