论文标题
二阶拓扑镁绝缘子中的手性铰链木元素
Chiral Hinge Magnons in Second-Order Topological Magnon Insulators
论文作者
论文摘要
当在凝结物质顺序中相互作用时，它们的基态波函数在拓扑上是微不足道的。尽管如此，在两个维度上，铁磁状态可以用非平凡拓扑（一种被称为拓扑镁绝缘子（TMI）的异国情调状态）支持自旋激发。在这里，我们从理论上揭开了揭幕，并在数字上确认了一个名为二阶TMI的三个维度的新型铁磁状态，其标志是其铰链上的激发，方面相交。由于铁磁性自然会带有破碎的时间反转对称性，因此铰链镁是手性的，使反向散射不可能。因此，他们踪影探索了一个三维路径，该路径涉及不受缺陷的样本，并受到光谱间隙的拓扑保护。通过样本终止的原子级工程，它们对疾病的强大和同时可调节。我们的发现赋予了高阶拓扑的工具，这是一条有前途的途径，这是一条有希望的途径，将低能信息转移与三维垂直整合相结合。
When interacting spins in condensed matter order ferromagnetically, their ground state wave function is topologically trivial. Nonetheless, in two dimensions, the ferromagnetic state can support spin excitations with nontrivial topology, an exotic state known as topological magnon insulator (TMI). Here, we theoretically unveil and numerically confirm a novel ferromagnetic state in three dimensions dubbed second-order TMI, whose hallmarks are excitations at its hinges, where facets intersect. Since ferromagnetism naturally comes with broken time-reversal symmetry, the hinge magnons are chiral, rendering backscattering impossible. Hence, they trace out a three-dimensional path about the sample unimpeded by defects and are topologically protected by the spectral gap. They are remarkably robust against disorder and simultaneously highly tunable by atomic-level engineering of the sample termination. Our findings empower magnonics with the tools of higher-order topology, a promising route to combine low-energy information transfer free of Joule heating with three-dimensional vertical integration.
