Skyrmion-induced anomalous Hall conductivity on topological insulator surfaces

Electron-spin momentum locking together with background magnetic textures can significantly alter the electron transport properties. We investigate theoretically the electron transport at the interface between a topological insulator and a magnetic insulator with magnetic skyrmions on the top. In contrast to the conventional topological Hall effect in normal metals, the skyrmions yield an additional contribution to the anomalous Hall conductivity even in the absence of in-plane magnetic texture, arising from the phase factor characteristic of Dirac electrons acquired at the skyrmion boundary.