Local moments in spin-orbit coupled systems

自旋轨道耦合系统中的局部矩

• 批准号: 435049553
• 负责人: Dr. Toshihiro Sato, Ph.D.
• 金额: --
• 依托单位: Institut für Theoretische Physik und Astrophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/435049553?language=en
• 关键词: Local; moments; spin; orbit; coupled

The interplay of spin-orbit coupling and electronic correlations leads to a variety of phenomena of current research in solid state physics. Examples include fractionalization and associated emergent gauge theories in generalized Kitaev models relevant for iridates, as well as magnetic adatoms on the surface of strong topological insulators. In this grant proposal, we aim at using exact auxiliary-field quantum Monte Carlo simulations to investigate thermodynamic and dynamical properties of such systems. The general problem of electronic correlations in spin-orbit coupled systems suffers from a negative sign problem that renders it exponentially hard. Here, the key technical insight is that we can use symmetry arguments to reduce the severity of the negative sign problem. This will allow us to access the high-temperature thermodynamic and dynamical properties of the above-mentioned systems and, for instance, probe for signatures of exceptional points in the single-particle spectral function. As for the doped Hubbard model, we foresee that we will be able to reach experimentally relevant energy scales. Our approach is based on a fermion representation of the spin operator. Within our formulation, one can avoid the negative sign problem by attaching an even flavor index to the fermions. Another goal of the proposal is to investigate these models, and in particular to address the question if they capture aspects of the physics of the flavorless ones.

自旋轨道耦合和电子关联的相互作用导致了当前固体物理研究中的各种现象。例子包括分馏和相关的紧急规范理论在广义Kitaev模型相关的虹膜，以及磁性吸附原子表面上的强拓扑绝缘体。在这项资助计划中，我们的目标是使用精确的量子蒙特卡罗模拟来研究这种系统的热力学和动力学性质。在自旋轨道耦合系统中，电子关联的一般问题都存在一个负符号问题，这使得它以指数方式变得困难。在这里，关键的技术见解是，我们可以使用对称性参数来减少负号问题的严重性。这将使我们能够获得上述系统的高温热力学和动力学性质，例如，探测单粒子谱函数中异常点的特征。至于掺杂的哈伯德模型，我们预见，我们将能够达到实验相关的能量尺度。我们的方法是基于自旋算符的费米子表示。在我们的公式中，我们可以通过给费米子附加一个均匀的味道指数来避免负号问题。该提案的另一个目标是调查这些模型，特别是解决他们是否捕捉无味的物理方面的问题。