发表机构
International Center for Quantum Materials, School of Physics, Peking University; Collaborative Innovation Center of Quantum Matter; Beijing Key Laboratory of Quantum Devices（北京大学物理学院量子材料科学中心; 量子物质协同创新中心; 北京量子器件重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过磁拓扑力学在三维Maxwell晶格阻挫Mott绝缘体中实现Kane-Lubensky型零能Weyl线声子，产生T²低温声子比热，为拓扑声子现象提供新平台。
AI 中文摘要
我们证明，在三维Maxwell晶格阻挫Mott绝缘体中，通过磁拓扑力学可以产生Kane-Lubensky类型的零能无隙Weyl线声子。在具有自旋-晶格耦合的烧绿石反铁磁体中，磁场选择自旋态，其晶格畸变生成$P4_3 32$拓扑晶格。更为关键的是，自旋-晶格耦合和自旋构型导致相邻键的弯曲，并将系统转变为拓扑Maxwell晶格。值得注意的是，所得系统被发现承载受拓扑保护的体零频Weyl线声子，且这些无隙声子不是Goldstone模式。与Goldstone声子的常规${C_{\rm ph}\sim T^3}$不同，这些一维零模流形产生特征性的低温声子比热${C_{\rm ph}\sim T^2}$。我们的结果可应用于基于Cr的尖晶石系统，此外，我们建立了一个低能平台，其中大量拓扑零频声子可以与其他自由度强耦合，为奇异的声子介导现象开辟了途径。
英文摘要
We show that zero-energy gapless Weyl-line phonons of the Kane-Lubensky's type can arise in the three-dimensional Maxwell lattice frustrated Mott insulators through the magnetopological mechanics. In a pyrochlore antiferromagnet with the spin-lattice coupling, a magnetic field selects the spin state whose lattice distortion generates a $P4_3 32$ topological lattice. More crucially, the spin-lattice coupling and the spin configuration cause the bending of the neighbouring bonds, and converts the system into the topological Maxwell lattice. Remarkably, the resulting system is found to host the bulk zero-frequency Weyl-line phonons protected topologically, and these gapless phonons are not Goldstone modes. Unlike the conventional ${C_{\rm ph}\sim T^3}$ for the Goldstone phonons, these one-dimensional zero-mode manifolds yield a characteristic low-temperature phonon specific heat ${C_{\rm ph}\sim T^2}$. Our results could find applications in the Cr-based spinel systems, and moreover, we establish a low-energy platform where an extensive number of topological zero-frequency phonons can strongly couple to other degrees of freedom, opening a route to exotic phonon-mediated phenomena.
Comments5 pages, 2 figures; Supplemental Material included (11 pages, 2 figures, 3 tables)
