Near itinerancy and slow singlet formation in the triangular lattice NaRuO2

Charles C. Tam; Alon Hendler Avidor; Pritam Bhattacharyya; Yongseong Choi; Daniel Haskel; Sven Luther; Hlynur Gretarsson; Liviu Hozoi; Stephen D. Wilson

arXiv · 2607.05287

Near itinerancy and slow singlet formation in the triangular lattice NaRuO2

Charles C. Tam·Alon Hendler Avidor·Pritam Bhattacharyya·Yongseong Choi·Daniel Haskel·Sven Luther·Hlynur Gretarsson·Liviu Hozoi·Stephen D. Wilson

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Abstract

NaRuO$_2$ forms a delafossite-like structure that contains triangular sublattices of edge-sharing RuO$_6$ octahedra. It shows no evidence of magnetic order down to 100 mK and persistent spin fluctuations, suggestive of a quantum disordered magnetic ground state. In order to characterize the physical regime from which this disordered state arises, we use resonant inelastic X-ray scattering (RIXS) and X-ray absorption spectroscopy (XAS) at the Ru-$L_{2,3}$-edge, along with pulsed high-field magnetization to characterize both the local electronic structure and the magnetic interactions. Despite significant spin-orbit coupling inferred from XAS measurements, a spin-orbit exciton, characteristic of a spin-orbit assisted Mott insulator, was not observed with RIXS due to the presence of damped intraorbital excitations, which are characteristic of a metal. Corroborated by models of the high-field magnetization to a random singlet model, we propose a picture of a nearly itinerant system with strong magnetic and charge fluctuations that destabilize long-range magnetic order.

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Charles C. Tam, Alon Hendler Avidor, Pritam Bhattacharyya, Yongseong Choi, Daniel Haskel, Sven Luther, Hlynur Gretarsson, Liviu Hozoi, Stephen D. Wilson. 2026-07-06. Near itinerancy and slow singlet formation in the triangular lattice NaRuO2. https://arxiv.org/abs/2607.05287

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