论文标题
在外部电磁场下驱动的，不均匀的绝缘子中纺纱拓扑作用的半经典处理
A semiclassical treatment of spinor topological effects in driven, inhomogeneous insulators under external electromagnetic fields
论文作者
论文摘要
在拓扑绝缘子的描述中引入内部自由度，导致了无数的理论和实验进步。特别令人感兴趣的是周期性扰动，无论是在时间还是空间上，它们都大大化了电子响应的种类，例如Thouless的电荷泵及其更高维度的表亲或更高阶段的拓扑绝缘子。在这里，我们开发了一种半经典的方法，用于在绝热驱动的，弱的尺寸的弱型旋转，山谷或原子轨道等一般旋转自由度的运输和积累。具体而言，我们专注于物理旋转，并在系统的时空调制中推导旋转电流和密度最高为三阶。然后，我们将这些贡献与几何和拓扑对象（旋转的通量和数字）联系起来，在系统的较高维相空间（即其组合的动量位置时间坐标）上定义。此外，我们通过引入电偶极，四极杆和八极矩的旋转类似物来提供我们的半经典分析与多极矩的现代理论之间的联系。结果显示在混凝土紧密结合模型中，在该模型中，通过分析诱导的响应进行了分析。
Introducing internal degrees of freedom in the description of topological insulators has led to a myriad of theoretical and experimental advances. Of particular interest are the effects of periodic perturbations, either in time or space, as they considerably enrich the variety of electronic responses, with examples such as Thouless's charge pump and its higher dimensional cousins, or, higher-order topological insulators. Here, we develop a semiclassical approach to transport and accumulation of general spinor degrees of freedom, such as physical spin, valley, or atomic orbits, in adiabatically driven, weakly inhomogeneous insulators of dimensions one, two and three under external electromagnetic fields. Specifically, we focus on physical spins and derive the spin current and density up to third order in the spatio-temporal modulations of the system. We, then, relate these contributions to geometrical and topological objects -- the spin-Chern fluxes and numbers -- defined over the higher-dimensional phase-space of the system, i.e., its combined momentum-position-time coordinates. Furthermore, we provide a connection between our semiclassical analysis and the modern theory of multipole moments by introducing spin analogues of the electric dipole, quadrupole and octapole moments. The results are showcased in concrete tight-binding models where the induced responses are calculated analytically.
