Observation of the quantum Hall effect in confined films of the three-dimensional Dirac semimetal Cd3As2

TL;DR

This study reports the observation of the quantum Hall effect in thin films of the 3D Dirac semimetal Cd3As2, highlighting surface state dominance and potential for quantum transport applications.

Contribution

It demonstrates the emergence of quantized Hall conductance due to surface states in thin Cd3As2 films, revealing new quantum phenomena in topological semimetals.

Findings

Energy gap opens in thin films

Surface states dominate transport at low temperatures

Quantized Hall effect observed in surface states

Abstract

The magnetotransport properties of epitaxial films of Cd3As2, a paradigm three-dimensional Dirac semimetal, are investigated. We show that an energy gap opens in the bulk electronic states of sufficiently thin films and, at low temperatures, carriers residing in surface states dominate the electrical transport. The carriers in these states are sufficiently mobile to give rise to a quantized Hall effect. The sharp quantization demonstrates surface transport that is virtually free of parasitic bulk conduction and paves the way for novel quantum transport studies in this class of topological materials. Our results also demonstrate that heterostructuring approaches can be used to study and engineer quantum states in topological semimetals.