发表机构
Research Center for Materials Nanoarchitectonics, National Institute for Materials Science（物质材料研究机构纳米结构研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过双轨道Kanamori-Hubbard模型，揭示了自旋-1反铁磁绝缘体在掺杂和温度下涌现电子模式的机制，并发现小轨道间排斥可形成三重态配对，为理解强关联系统非常规量子现象提供新视角。
AI 中文摘要
传统能带绝缘体的电子能带结构通常在化学势移动或温度升高引起的掺杂下保持不变。然而，在由Hubbard模型和Kondo晶格模型等描述的Mott和Kondo绝缘体中，已证明具有动量移动的磁色散关系的不同电子模式会从带边出现并进入带隙。本文通过研究双轨道Kanamori-Hubbard模型，阐明了自旋-1反铁磁绝缘体的能带结构如何以及为何随掺杂和温度变化，揭示了轨道简并系统特有的涌现光谱特征。利用弱跳跃有效理论、选择定则分析和数值计算，明确了涌现电子模式的性质。在典型参数区域中，每个轨道中掺杂诱导的模式反映不同类型的自旋模式，而温度诱导的模式主要反映两个轨道中的低能自旋模式；在两种情况下，涌现模式均表现出动量移动的自旋模式色散关系。如果跳跃参数的符号不同，这些涌现模式的动量区域可能因轨道而异。对于较小的轨道间排斥，掺杂后可形成在位自旋三重态对，导致破对能隙，而温度诱导的电子模式继续反映低能自旋模式，无破对能隙。此外，还阐明了自旋或电荷扰动下非平衡态中电子模式的出现和特征。这些发现为理解大自旋反铁磁绝缘体中自旋、电荷和轨道自由度之间的相互作用如何导致涌现电子模式提供了全面的认识，为探索强关联系统中的非常规量子现象开辟了途径。
英文摘要
The electronic band structures of conventional band insulators generally remain unchanged under doping via chemical-potential shifts or increasing temperature. However, in Mott and Kondo insulators described by models such as the Hubbard and Kondo lattice models, distinct electronic modes with momentum-shifted magnetic dispersion relations have been shown to emerge from band edges into the gap. Here, by investigating the two-orbital Kanamori-Hubbard model, this study elucidates how and why the band structures of spin-1 antiferromagnetic insulators change with doping and temperature, revealing emergent spectral features characteristic of orbitally degenerate systems. The nature of the emergent electronic modes is clarified using weak-hopping effective theory, selection-rule analysis, and numerical calculations. In a typical parameter regime, the doping-induced modes in each orbital reflect distinct types of spin modes, while the temperature-induced modes primarily reflect the low-energy spin mode in both orbitals; in both cases, the emergent modes exhibit momentum-shifted spin-mode dispersion relations. The momentum regimes of these emergent modes can differ between orbitals if signs of the hopping parameters differ. For small inter-orbital repulsion, onsite spin-triplet pairs can form after doping, leading to a pair-breaking gap, while the temperature-induced electronic modes continue to reflect the low-energy spin mode without a pair-breaking gap. Moreover, the emergence and characteristics of electronic modes in nonequilibrium states by spin or charge perturbations are elucidated. These findings provide a comprehensive understanding of how the interplay among the spin, charge, and orbital degrees of freedom in large-spin antiferromagnetic insulators leads to emergent electronic modes, opening avenues for exploring unconventional quantum phenomena in strongly correlated systems.
Comments26 pages, 11 figures, 1 table
