Magnon interactions in a moderately correlated Mott insulator.
basic_science · Level V
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- Record sourced from PubMed, PMID 38914556.
- Also identified by DOI 10.1038/s41467-024-49714-y and PMC identifier 11196644.
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Abstract
Quantum fluctuations in low-dimensional systems and near quantum phase transitions have significant influences on material properties. Yet, it is difficult to experimentally gauge the strength and importance of quantum fluctuations. Here we provide a resonant inelastic x-ray scattering study of magnon excitations in Mott insulating cuprates. From the thin film of SrCuO<sub>2</sub>, single- and bi-magnon dispersions are derived. Using an effective Heisenberg Hamiltonian generated from the Hubbard model, we show that the single-magnon dispersion is only described satisfactorily when including significant quantum corrections stemming from magnon-magnon interactions. Comparative results on La<sub>2</sub>CuO<sub>4</sub> indicate that quantum fluctuations are much stronger in SrCuO<sub>2</sub> suggesting closer proximity to a magnetic quantum critical point. Monte Carlo calculations reveal that other magnetic orders may compete with the antiferromagnetic Néel order as the ground state. Our results indicate that SrCuO<sub>2</sub>-due to strong quantum fluctuations-is a unique starting point for the exploration of novel magnetic ground states.