Hamilton Colloquium Series

The anomalous Hall effect was discovered more than 130 years ago in a ferromagnet, where a Hall resistance exists even in the absence of external magnetic field. The quantized version of the anomalous Hall effect has attracted much interest since the discovery of the quantum Hall effect in the 1980s. A few years ago, it was proposed that a quantum anomalous Hall effect may occur in magnetic topological insulators, but the experimental realization has been elusive. In this talk we will report transport studies of magnetically doped topological insulator thin films grown by molecular beam epitaxy. We have achieved systematic tuning of the electronic band structure, magnetic ordering, and bulk band topology, which eventually led to the experimental realization of the quantum anomalous Hall effect, i.e., the quantum Hall effect in zero magnetic field.

Reference:
“Experimental observation of the quantum anomalous Hall effect in a magnetic topological insulator,” Science, 340, 167 (2013).