Online Archive

November 2, 2010 16:15 - 17:15

Empa, Dübendorf, Theodor-Erismann-Auditorium, VE102


Prof. Jürg Osterwalder, Physik-Institut, Universität Zürich

Leadership of diskussion

Prof. Dr Roman Fasel, Empa


Materials like Bi-Sb alloys, Bi2Se3 or Bi2Te3 have been known and studied for decades, mostly for their interesting thermoelectrical properties. In common they are insulators with relatively small band gaps, which are opened by the spin-orbit interaction. Quite recently, it was recognized that the topology of the electronic states separated by this gap is non-trivial. Wherever such a material is in contact with a normal material or with vacuum, these states have to cross the gap, thus form conducting interface or surface states. These are thus topologically protected. Moreover, the spin-orbit interaction renders these states fully spin polarized, with opposite spins moving in opposite directions. A topological insulator has thus an insulating bulk with a highly conducting nanometer thick skin that carries spin currents analogous to those in the quantum spin Hall effect. The recent literature is replete with new phenomena and concepts that could be realized with such materials. An introduction to the new aspects of these materials will be given as well as a review of some of the recent experimental demonstrations that new physics is indeed found.


The language of the presentation is English.
Free entrance, guests are welcome

Vortragssprache: Englisch