Ambi-chiral anomalous Hall effect in magnetically doped topological insulators

The chirality associated with broken time-reversal symmetry in magnetically doped topological insulators has important implications for the quantum transport phenomena. Here we report anomalous Hall effect studies in Mn- and Cr-doped Bi2Te3 topological insulators with varied thicknesses and doping contents. By tracing the magnitude of the anomalous Hall resistivity, we find that the Mn-type anomalous Hall effect characterized with clockwise chirality is strengthened by the reduction of film thickness, which is opposite to that of the Cr-type anomalous Hall effect with counterclockwise chirality. We provide a phenomenological physical picture to explain the evolution of the magnetic order and the anomalous Hall chirality in magnetically doped topological insulators.