Topological insulators are candidates to open up a novel route in spin based electronics. Different to traditional ferromagnetic materials, where the carrier spin-polarization and magnetization are based on the exchange interaction, the spin properties in topological insulators are based on the coupling of spin- and orbit interaction connected to its momentum. Specific ways to control the spin-polarization with light have been demonstrated: the energy momentum landscape of the Dirac cone provides spin-momentum locking of the charge current and its spin. The directionality of spin and momentum, as well as control with light has been demonstrated. Here we demonstrate a coherent femtosecond control of spin-polarization for states in the valence band at around the Dirac cone.
@article{arxiv.1506.02692,
title = {Coherent ultrafast spin-dynamics probed in three dimensional topological insulators},
author = {F. Boschini and M. Mansurova and G. Mussler and J. Kampmeier and D. Grützmacher and L. Braun and F. Katmis and J. S. Moodera and C. Dallera and E. Carpene and C. Franz and M. Czerner and C. Heiliger and T. Kampfrath and M. Münzenberg},
journal= {arXiv preprint arXiv:1506.02692},
year = {2016}
}