近日，美国哈佛大学Markus Greiner团队报道了多波段Hubbard系统中超冷费米子的铁磁性。2026年5月7日出版的《科学》杂志发表了这项成果。

强关联材料具有多个电子轨道，这对于准确理解其多体性质至关重要。在此类多带模型中，量子干涉可以导致高度简并的平带，从而产生巡游磁相。

研究组报道了在利用超冷费米子实现的利布晶格中观测到的亚铁磁态的特征，该态的特点是具有反铁磁关联的反向排列磁矩，并伴随有限的自旋极化。当将排斥相互作用从弱相互作用区域逐渐增强到海森堡区域时，这些特征依然稳健；并且在将晶格原胞从正方形连续调谐到利布几何结构时，这些特征也会出现。这种灵活的方法为探索奇异量子相（如kagome晶格中的量子自旋液体和近藤模型中的重费米子行为）铺平了道路。

附：英文原文

Title: Ferrimagnetism of ultracold fermions in a multiband Hubbard system

Author: Martin Lebrat, Anant Kale, Lev Haldar Kendrick, Muqing Xu, Youqi Gang, Alexander Nikolaenko, Pietro M. Bonetti, Subir Sachdev, Markus Greiner

Issue&Volume: 2026-05-07

Abstract: Strongly correlated materials feature multiple electronic orbitals, which are crucial to accurately understanding their many-body properties. In such multiband models, quantum interference can lead to flat energy bands with large degeneracy that gives rise to itinerant magnetic phases. We report on signatures of a ferrimagnetic state realized in a Lieb lattice with ultracold fermions, characterized by antialigned magnetic moments with antiferromagnetic correlations, and concomitant with a finite spin polarization. The signatures remain robust when increasing repulsive interactions from the weakly interacting to the Heisenberg regime and emerge when continuously tuning the lattice unit cell from a square to a Lieb geometry. Our flexible approach paves the way toward exploring exotic phases, such as quantum spin liquids in kagome lattices and heavy fermion behavior in Kondo models.

DOI: adq2411

Source: https://www.science.org/doi/10.1126/science.adq2411