FisMat2017 - Submission - View

Abstract's title: Robust spin-polarized midgap states at step edges of topological crystalline insulators
Submitting author: Domenico Di Sante
Affiliation: Universitaet Wuerzburg
Affiliation Address: Institut fuer Theoretische Physik und Astrophysik Universitaet Wuerzburg Am Hubland 97074 Wuerzburg - (Germany) office: M1 - 03.016 (Campus Sued)
Country: Germany
Oral presentation/Poster (Author's request): Oral presentation
Other authors and affiliations: Paolo Sessi [2] AND Martin Greiter [1] AND Titus Neupert [3] AND Giorgio Sangiovanni [1] AND Tomasz Story [4] AND Ronny Thomale [1] and Matthias Bode [2] [2] Experimentelle Physik II Universitaet Wuerzburg, Germany AND [3] Physik-Institut Universitaet Zuerich, Switzerland AND [4] Institute of Physics Polish Academy of Sciences, 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. 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.


[1] P. Sessi, D. Di Sante, A. Szczerbakow, F. Glott, S. Wilfert, H. Schmidt, 
T. Bathon, P. Dziawa, M. Greiter, T. Neupert, G. Sangiovanni, T. Story, R. Thomale and M. Bode, Science 354, 1269 (2016)