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arXiv 2603.17818cond-mat.str-el
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铁磁性、电子输运与强关联系统中的无序

Magnetism, electronic transport, and disorder in strongly correlated systems

University of Buenos Aires(布宜诺斯艾利斯大学)

Joel Bobadilla

AI总结:

本文研究强关联电子系统的磁性、能谱和输运性质,重点探讨Hubbard模型及其在实际材料中的扩展。通过动态平均场理论框架,探讨相互作用强度、温度、掺杂和磁场的不同区域,揭示局部电子关联在能谱重构和非平凡输运响应中的核心作用。

摘要:

本论文研究强关联电子系统的磁性、能谱和输运性质,重点探讨Hubbard模型及其在实际材料中的扩展。在动态平均场理论(DMFT)框架内,探讨不同相互作用强度、温度、掺杂和磁场的区域,突出局部电子关联在能谱重构和非平凡输运响应中的核心作用。对于受Zeeman场作用的反铁磁Hubbard模型,研究磁电阻和局部反磁性,揭示与电荷和自旋自由度相关的不同能量尺度的共存。识别出一种最小的、纯粹由关联驱动的机制,用于在结构常规的列状反铁磁体中产生自旋极化的电荷输运,该机制受粒子-空穴对称性和反铁磁子晶格等价性的同时破坏控制。最后,将这些概念应用于具有强自旋-轨道耦合的关联材料,如Sr₂IrO₄和Sr₃Ir₂O₇,以及受库仑阻塞和无序主导的纳米颗粒固体。结果表明,关联晶格模型中发展出的概念为复杂系统中的金属-绝缘体转变和能谱重构提供了统一的解释。

英文摘要:

This thesis investigates the magnetic, spectral, and transport properties of strongly correlated electronic systems, with a primary focus on the Hubbard model and its extensions relevant for real materials. Within the dynamical mean-field theory (DMFT) framework, different regimes of interaction strength, temperature, doping, and magnetic field are explored, highlighting the central role of local electronic correlations in shaping spectral reconstruction and nontrivial transport responses. For the antiferromagnetic Hubbard model under a Zeeman field, magnetoresistance and local metamagnetism are characterized, revealing the coexistence of distinct energy scales associated with charge and spin degrees of freedom. A minimal, purely correlation-driven mechanism for generating spin-polarized charge transport in structurally conventional collinear antiferromagnets is identified, controlled by the simultaneous breaking of particle--hole symmetry and antiferromagnetic sublattice equivalence. Finally, these concepts are applied to correlated materials with strong spin--orbit coupling, such as Sr$_2$IrO$_4$ and Sr$_3$Ir$_2$O$_7$, and to nanoparticle solids dominated by Coulomb blockade and disorder. The results show how ideas developed in correlated lattice models provide a unified interpretation of metal--insulator transitions and spectral reconstruction in complex systems.

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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