In the conventional quantum Hall effect, a two-dimensional electronic system in the presence of a magnetic field forms metallic conduction paths at the edge of the sample. This paper experimentally demonstrates a sought-after three-dimensional and spontaneous version of this effect; the bulk of a Bi0.9Sb0.1 crystal is shown to be insulating, while two-dimensional metallic conduction paths exist at the surface, without any applied magnetic field.
- D. Hsieh
- D. Qian
- M. Z. Hasan