AI 中文总结
采用动力学平均场理论研究双轨道哈伯德模型，明确轨道间库仑相互作用诱导的电荷竞争是异常轨道重构的关键机制，洪德耦合可调控该过程，为理解低维过渡金属氧化物的轨道现象提供统一图像。
AI 中文摘要
一类低维关联氧化物中异常轨道极化的微观起源尚未明确，原因在于晶体场效应、电子关联与轨道依赖维度之间的竞争。我们采用动力学平均场理论，研究具有轨道依赖维度的双轨道哈伯德模型，揭示了超越纯晶体场图像的异常轨道重构机制。我们确定轨道间库仑相互作用诱导的电荷竞争是轨道重新分布的关键微观机制，该机制首先形成轨道极化关联金属，随后形成轨道极化莫特绝缘体。我们还发现洪德耦合是轨道重构的填充依赖调控因子：在四分之一填充时，它通过与轨道间电荷涨落竞争，削弱关联诱导的轨道重新分布；在半填充时，它通过稳定高自旋轨道平衡构型，完全抑制轨道极化态。这些结果为关联驱动的轨道重构提供了统一图像，并强调了轨道间相互作用与洪德耦合对理解低维过渡金属氧化物中轨道现象的重要性。
英文摘要
The microscopic origin of anomalous orbital polarization in a class of low-dimensional correlated oxides remains unresolved due to the competition among crystal-field effects, electronic correlations, and orbital-dependent dimensionality. Using dynamical mean-field theory, we investigate a two orbital Hubbard model with orbital-dependent dimensionality and reveal the mechanism for anomalous orbital polarization through orbital reconstruction beyond the bare crystal-field picture. We identify interorbital Coulomb interaction-induced charge competition as a key microscopic mechanism responsible for the orbital redistribution, which leads first to an orbital-polarized correlated metal and subsequently to an orbital-polarized Mott insulator. We further find that Hund's coupling acts as a filling-dependent regulator of orbital reconstruction. It weakens the correlation-induced orbital redistribution at quarter filling by competing with interorbital charge fluctuations, while at half filling it completely suppresses the orbital-polarized state by stabilizing high-spin orbital-balanced configurations. These results provide a unified picture of correlation driven orbital reconstruction and highlight the relevance of interorbital interactions and Hund's coupling for understanding orbital phenomena in low-dimensional transition-metal oxides.
Comments12 pages, 10 figures
