Semiclassical treatment of spinor topological effects in driven inhomogeneous insulators under external electromagnetic fields

Article

关键词: EARTH IRON-ALLOYS;    BERRY PHASE;    MAGNETOELECTRIC COMPOSITE;    PIEZOELECTRIC CERAMICS;    CHERN NUMBER;    HYPERORBITS;    DYNAMICS;    SOLITONS;    BANDS;    PUMP;   

DOI  :  10.1103/PhysRevB.106.165130

来源: SCIE

【 摘 要 】

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 1, 2, and 3, under external electromagnetic fields. Specifically, we derive the spinor current and density up to third order in the spatiotemporal modulations of the system and relate the induced responses to geometrical and topological objects-the spinor-Chern fluxes and numbers-defined over the higher-dimensional phase space of the system, i.e., its combined position-momentum-time coordinates. Furthermore, we provide a connection between our semiclassical analysis and the modern theory of multipole moments by introducing spinor analogs of the electric dipole, quadrupole, and octupole moments. The results are showcased in concrete tight-binding models where spinor transport and accumulation are calculated analytically.

【 授权许可】

Free