High quality thin films of the intrinsic magnetic topological insulator MnBi2Te4 were studied by means of optical spectroscopy in a broad spectral range from THz to UV. By analysing the optical conductivity at room temperature for different thickness, the presence of surface topological states superimposed to the bulk electrodynamics response was highlighted. For the thinnest film, where charge transport is dominated by the Dirac surface states, the interplay between the magnetic phase transition and the topological surface states was investigated. Crossing the Neèl temperature, the optical conductivity measurements indicate the opening of a magnetic gap at the Dirac node
- Luca Tomarchio
- Lorenzo Mosesso
- Stefano Lupi
