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arXiv 2202.05029cond-mat.str-el
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莫尔材料中的矩和多重态:自旋谷模型的赝费米子泛函重整化群

Moments and multiplets in moiré materials: A pseudo-fermion functional renormalization group for spin-valley models

Lasse Gresista, Dominik Kiese, Simon Trebst

摘要:

莫尔系统中强关联态的观测重新激发了人们对具有更高SU(4)自旋对称性的磁系统的概念兴趣,例如描述局部矩为耦合自旋谷自由度的莫特绝缘体。在这里,我们讨论了一个数值重整化群计划,探讨自旋谷有序和非常规自旋谷液态的形成在零温度下的基础上的伪费米子表示。我们推广了传统的$\mathfrak{su}$(2)自旋的伪费米子泛函重整化群方法,能够处理$\mathfrak{su}$(4)代数自共轭表示中一般自旋-谷交换哈密顿量的对角和非对角耦合.为了实现适当的数值效率,我们推导出一些对称性约束的流量方程,显着限制了要解决的常微分方程的数量。作为一个例子,我们研究了三角晶格上的一个对角SU(2)$_{\textrm{spin}}$ $\otimes$ U(1)$_{\textrm{valley}}$模型,该模型具有丰富的自旋和谷序相图.

英文摘要:

The observation of strongly-correlated states in moiré systems has renewed the conceptual interest in magnetic systems with higher SU(4) spin symmetry, e.g. to describe Mott insulators where the local moments are coupled spin-valley degrees of freedom. Here, we discuss a numerical renormalization group scheme to explore the formation of spin-valley ordered and unconventional spin-valley liquid states at zero temperature based on a pseudo-fermion representation. Our generalization of the conventional pseudo-fermion functional renormalization group approach for $\mathfrak{su}$(2) spins is capable of treating diagonal and off-diagonal couplings of generic spin-valley exchange Hamiltonians in the self-conjugate representation of the $\mathfrak{su}$(4) algebra. To achieve proper numerical efficiency, we derive a number of symmetry constraints on the flow equations that significantly limit the number of ordinary differential equations to be solved. As an example system, we investigate a diagonal SU(2)$_{\textrm{spin}}$ $\otimes$ U(1)$_{\textrm{valley}}$ model on the triangular lattice which exhibits a rich phase diagram of spin and valley ordered phases.

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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