标题： 锂修饰的范德华铁磁体Fe$_3$GeTe$_2$中纳米尺度自旋涡的长寿命 显示英文标题

标题： Long lifetimes of nanoscale skyrmions in lithium-decorated van der Waals ferromagnet Fe$_3$GeTe$_2$

摘要： 由于自旋-轨道耦合并依赖于反演对称性的破坏，Dzyaloshinskii-Moriya相互作用（DMI）被认为是形成磁性斯格明子的关键因素。 然而，大多数二维磁体表现出反演对称性；因此，DMI被抑制。 在这里，我们提出了一种通过在二维磁体表面吸收锂来诱导大DMI的策略——一种实验上可行的方法。 使用第一性原理和原子自旋模拟，我们预测在锂修饰的单层Fe$_3$GeTe$_2$中，在施加小的垂直磁场（$B_z$）的情况下形成纳米尺度的斯格明子。 值得注意的是，我们在$B_z = 0.4$ T时发现非常大的斯格明子能量势垒，超过300 meV，与铁磁体/重金属界面观察到的相当。 这些独特斯格明子的起源归因于强DMI、交换挫败和小磁晶各向异性能之间的竞争。 我们进一步表明，亚稳态斯格明子的寿命在温度高达75 K时超过一小时。 显示英文摘要

摘要： The Dzyaloshinskii-Moriya interaction (DMI), which originates from spin-orbit coupling and relies on broken inversion symmetry, is recognized as a key ingredient in forming magnetic skyrmions. However, most 2D magnets exhibit inversion symmetry; therefore, the DMI is suppressed. Here, we propose a strategy to induce large DMI via lithium absorption on the surface of 2D magnets -- an experimentally feasible approach. Using first-principles and atomistic spin simulations, we predict the formation of nanoscale skyrmions in lithium-decorated monolayer Fe$_3$GeTe$_2$ by imposing small out-of-plane magnetic fields ($B_z$). Notably, we find very large skyrmion energy barriers of more than 300 meV at $B_z = 0.4$ T, comparable to those observed in ferromagnet/heavy-metal interfaces. The origin of these unique skyrmions is attributed to the competition between strong DMI, exchange frustration, and small magnetocrystalline anisotropy energy. We further show that the lifetimes of metastable skyrmions exceed one hour for temperatures up to 75 K.