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arXiv · 2307.15100

Singlet magnetism in intermetallic UGa$_2$ unveiled by inelastic x-ray scattering

Andrea Marino·Martin Sundermann·Denise S. Christovam·Andrea Amorese·Chun-Fu Chang·Paulius Dolmantas·Ayman H. Said·Hlynur Grrtarsson·Bernhard Keimer·Maurits W. Haverkort·Alexander V. Andreev·Ladilav Havela·Peter Thalmeier·Liu Hao Tjeng·Andrea Severing
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Abstract

Using high resolution tender-x-ray resonant inelastic scattering and hard-x-ray non-resonant inelastic scattering beyond the dipole limit we were able to detect electronic excitations in intermetallic UGa$_2$ that are highly atomic in nature. Analysis of the spectral lineshape reveals that the local $5f^2$ configuration characterizes the correlated nature of this ferromagnet. The orientation and directional dependence of the spectra indicate that the ground state is made of the $\Gamma_1$ singlet and/or $\Gamma_6$ doublet symmetry. With the ordered moment in the $ab$ plane, we infer that the magnetism originates from the higher lying $\Gamma_6$ doublet being mixed with the $\Gamma_1$ singlet due to inter-site exchange, qualifying UGa$_2$ to be a true quantum magnet. The ability to observe atomic excitations is crucial to resolve the on-going debate about the degree of localization versus itineracy in U intermetallics.

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Andrea Marino, Martin Sundermann, Denise S. Christovam, Andrea Amorese, Chun-Fu Chang, Paulius Dolmantas, Ayman H. Said, Hlynur Grrtarsson, Bernhard Keimer, Maurits W. Haverkort, Alexander V. Andreev, Ladilav Havela, Peter Thalmeier, Liu Hao Tjeng, Andrea Severing. 2023-07-27. Singlet magnetism in intermetallic UGa$_2$ unveiled by inelastic x-ray scattering. https://doi.org/10.1103/physrevb.108.045142

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