Berlin 2018 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 44: Topological Insulators II (joint session TT/MA)
MA 44.1: Vortrag
Donnerstag, 15. März 2018, 09:30–09:45, A 053
Robust spin-polarized midgap states at step edges of topological crystalline insulators — •Domenico Di Sante1, Paolo Sessi2, Martin Greiter1, Titus Neupert3, Giorgio Sangiovanni1, Tomasz Story4, Ronny Thomale1, and Matthias Bode2 — 1Institut fuer Theoretische Physik, Universitaet Wuerzburg — 2Experimentelle Physik II, Universitaet Wuerzburg — 3Physik Institut, Universitaet Zuerich, Switzerland — 4Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
Topological crystalline insulators are materials in which the
crystalline symmetry leads to topologically protected surface states
with a chiral spin texture, rendering them potential candidates for
spintronics applications. In this talk, I report on the discovery of
one dimensional midgap states at odd atomic surface step edges of the
three dimensional topological crystalline insulator (Pb,Sn)Se. A
minimal toy model and realistic tight-binding calculations identify them
as spin polarized flat bands connecting two Dirac points. The midgap
states inherit stability through the two dimensional Dirac metal from
the three dimensional bulk insulator. This makes (Pb,Sn)Se the first
example for a crystal symmetry protected hierarchy of one and
two dimensional topological modes, which we experimentally prove to
result in a striking robustness to defects, strong magnetic fields, and
elevated temperature.
P.Sessi, D. Di Sante et. al, Science 354 1269 (2016)