Manifestation of axion electrodynamics through magnetic ordering on edges of a topological insulator

摘要: Because topological surface states of a single-crystal insulator can exist on all surfaces with different crystal orientations enclosing the crystal, mutual interactions among those contiguous to each other through edges lead unique phenomena inconceivable in normal insulators. Here we show, based first-principles approach, that difference work function between adjacent crystal-face generates built-in electric field around facet prototypical such as Bi2Se3. Owing magnetoelectric coupling for given broken time-reversal symmetry field, turn, forces effective magnetic dipoles accumulate along edges, realizing facet-edge ordering. We demonstrate predicted ordering is fact manifestation axion electrodynamics real solids.