2023-09-12 ブラウン大学
◆研究者たちは、不規則性という要素が量子スピン液体の理論とどのように関連しているかを調査し、不規則性が量子スピン液体の性質を変えることを発見しました。材料は量子スピン液体に近いが、新しい不規則な物質相である可能性があるとされています。この研究は、不規則性が量子システムに与える影響を理解し、量子コンピューティングに利用される可能性のある材料の探索に重要な示唆を提供しています。
＜関連情報＞
- https://www.brown.edu/news/2023-09-12/quantum-spin-liquids
- https://www.nature.com/articles/s41467-023-40769-x
ハニカムイリデートH3LiIr2O6における運動量非依存磁気励起連続体 Momentum-independent magnetic excitation continuum in the honeycomb iridate H3LiIr2O6
A. de la Torre,B. Zager,F. Bahrami,M. H. Upton,J. Kim,G. Fabbris,G.-H. Lee,W. Yang,D. Haskel,F. Tafti & K. W. Plumb
Nature Communications Published:DOI:https://doi.org/10.1038/s41467-023-40769-x
Abstract
Understanding the interplay between the inherent disorder and the correlated fluctuating-spin ground state is a key element in the search for quantum spin liquids. H3LiIr2O6 is considered to be a spin liquid that is proximate to the Kitaev-limit quantum spin liquid. Its ground state shows no magnetic order or spin freezing as expected for the spin liquid state. However, hydrogen zero-point motion and stacking faults are known to be present. The resulting bond disorder has been invoked to explain the existence of unexpected low-energy spin excitations, although data interpretation remains challenging. Here, we use resonant X-ray spectroscopies to map the collective excitations in H3LiIr2O6 and characterize its magnetic state. In the low-temperature correlated state, we reveal a broad bandwidth of magnetic excitations. The central energy and the high-energy tail of the continuum are consistent with expectations for dominant ferromagnetic Kitaev interactions between dynamically fluctuating spins. Furthermore, the absence of a momentum dependence to these excitations are consistent with disorder-induced broken translational invariance. Our low-energy data and the energy and width of the crystal field excitations support an interpretation of H3LiIr2O6 as a disordered topological spin liquid in close proximity to bond-disordered versions of the Kitaev quantum spin liquid.
