Surface state charge dynamics of a high-mobility three dimensional   topological insulator
  We present a magneto-optical study of the three-dimensional topological insulator, strained HgTe using a technique which capitalizes on advantages of time-domain spectroscopy to amplify the signal from the surface states. This measurement delivers valuable and precise information regarding the surface state dispersion within <1 meV of the Fermi level. The technique is highly suitable for the pursuit of the topological magnetoelectric effect and axion electrodynamics. 
Jason N. Hancock, J. L. M. van Mechelen, Alexey B. Kuzmenko, Dirk van   der Marel, Cristoph Br\"une, Elina G. Novik, Georgy ...
cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.str-el