arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.10825cond-mat.str-elcond-mat.quant-gas
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自旋介导的莫特激子

Spin-Mediated Mott Excitons

T. -S. Huang, C. L. Baldwin, M. Hafezi, V. Galitski

AI总结:

本研究理论探讨磁有序对莫特-哈伯德激子的影响,发现自旋介导的双占据子-空穴配对随Néel序增强而结合能增大、质量减小,与铱酸盐实验趋势一致,并可为超冷原子莫特绝缘体提供参考。

摘要:

受近期关于莫特绝缘体(包括铱酸盐和超冷原子)实验的启发,我们从理论上研究了磁有序对莫特-哈伯德激子的影响。具体而言,我们聚焦于哈伯德材料中自旋介导的双占据子-空穴配对。我们使用了多种互补的理论技术:用平均场理论描述自旋自由度,用自洽玻恩近似表征跨越哈伯德间隙的单个电荷激发,并用贝特-萨尔皮特方程识别双占据子和空穴的束缚态。我们发现,哈伯德激子的结合能随着Néel有序参数的增大而增加,而激子质量则减小。我们观察到,这些趋势在很大程度上依赖于有效相互作用的延迟效应,并且需要考虑改变磁有序所带来的多种影响。我们的结果与近期铱酸盐实验中观察到的关键定性趋势一致。此外,这些发现可能对超冷原子莫特绝缘体产生直接影响,因为在超冷原子体系中,哈伯德模型是对系统的精确描述,且微观自由度可以被直接探测。

英文摘要:

Motivated by recent experiments on Mott insulators, in both iridates and ultracold atoms, we theoretically study the effects of magnetic order on the Mott-Hubbard excitons. In particular, we focus on spin-mediated doublon-holon pairing in Hubbard materials. We use several complementary theoretical techniques: mean-field theory to describe the spin degrees of freedom, the self-consistent Born approximation to characterize individual charge excitations across the Hubbard gap, and the Bethe-Salpeter equation to identify bound states of doublons and holons. The binding energy of the Hubbard exciton is found to increase with increasing the N{é}el order parameter, while the exciton mass decreases. We observe that these trends rely significantly on the retardation of the effective interaction, and require consideration of multiple effects from changing the magnetic order. Our results are consistent with the key qualitative trends observed in recent experiments on iridates. Moreover, the findings could have direct implications on ultracold atom Mott insulators, where the Hubbard model is the exact description of the system and the microscopic degrees of freedom can be directly accessed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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