论文标题
在呼吸的pyrochlore晶格中，竞争量子自旋液体，量规波动和各向异性相互作用
Competing quantum spin liquids, gauge fluctuations, and anisotropic interactions in a breathing pyrochlore lattice
论文作者
论文摘要
我们使用投影对称组分析对$ s = 1/2 $ pyrochlore磁铁的量子自旋液体进行分类，并具有呼吸各向异性。我们发现40美元$ \ mathbb {z} _2 $旋转液体和16 $ u（1）$旋转液体，尊重$ f \ bar {4} 3m $ space group和时间反向对称性。作为一个应用程序，我们考虑使用反铁磁性海森堡模型，该模型被认为是候选材料中的主要交互，ba $ _3 $ yb $ yb $ _2 $ zn $ _5 $ o $ $ _ {11} $。专注于$ u（1）$ spin Liquid Ansatze，我们发现其中只有两个是物理上的，仅限于此模型。我们为这两个$ u（1）$旋转液体中的每一个提供了一个分析解决方案。据透露，其中一个人具有无间隙，而另一个则散发出Spinon激发。无论呼吸各向异性的程度如何，两个$ u（1）$旋转液体的能量都相等，并且可以通过低温热容量与四次分散无间隙的旋转子区分。我们进一步表明，后者不受随机相近似中$ u（1）$量规场的波动的影响。最后，我们证明了一个小的dzyaloshinskii-moriya相互作用可以提高两个$ u（1）$旋转液体之间的变性，最终导致晶格在强耦合时将晶格解散成独立的四面体。尽管BA $ _3 $ yb $ _2 $ zn $ _5 $ _5 $ o $ _ {11} $的当前模型参数确实将其放置在脱成式制度中，但其他候选材料可能会在不久的将来合成，以意识到我们工作中讨论的旋转液态。
We use the projective symmetry group analysis to classify the quantum spin liquids on the $S=1/2$ pyrochlore magnet with a breathing anisotropy. We find 40 $\mathbb{Z}_2$ spin liquids and 16 $U(1)$ spin liquids that respect the $F\bar{4}3m$ space group and the time reversal symmetry. As an application, we consider the antiferromagnetic Heisenberg model, which is proposed to be the dominant interaction in the candidate material Ba$_3$Yb$_2$Zn$_5$O$_{11}$. Focusing on the $U(1)$ spin liquid ansatze, we find that only two of them are physical when restricted to this model. We present an analytical solution to the parton mean field theory for each of these two $U(1)$ spin liquids. It is revealed that one of them has gapless, while the other one has gapped, spinon excitations. The two $U(1)$ spin liquids are equal in energy regardless of the degree of breathing anisotropy, and they can be differentiated by the low-temperature heat capacity contribution from the quadratically-dispersing gapless spinons. We further show that the latter is unaffected by fluctuations of the $U(1)$ gauge field within the random phase approximation. Finally, we demonstrate that a small Dzyaloshinskii-Moriya interaction lifts the degeneracy between the two $U(1)$ spin liquids, and it eventually causes the lattice to decouple into independent tetrahedra at strong coupling. While current model parameters for Ba$_3$Yb$_2$Zn$_5$O$_{11}$ place it indeed in the decoupled regime, other candidate materials may be synthesised in the near future that realize the spin liquid states discussed in our work.
