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O: Fachverband Oberflächenphysik

O 94: Topology and Symmetry-Protected Materials

O 94.3: Talk

Friday, March 31, 2023, 11:00–11:15, GER 38

Doping of coupled 1D topologically protected edge states on the (001) surface of the topological crystalline insulator (Pb,Sn)Se — •Florian Keller, Artem Odobesko, and Matthias Bode — Physikalisches Institut, Lehrstuhl für Experimentelle Physik II, Julius-Maximilians-Universität Würzburg, Würzburg, Germany

Topological crystalline insulators (TCI) are a class of materials with topological protected surface states protected by crystalline symmetry. One representative of this material class is (Pb,Sn)Se which exhibits Dirac fermions at the surface and topologically protected one-dimensional edge state at the step edges with a height equivalent to an odd number of atomic layers [1]. It was shown that the 1D edge states hybridize when two or more odd step edges are in close proximity [2]. The nature of this hybridization indicates that the quasiparticle edge mode is not an infinite quantum 1D state, but is either strongly localized or has a very short coherence length along the edge. One way to check this hypothesis is to increase the coherence length by shifting the Dirac energy close to the Fermi energy [3]. Here we present experiments where Fe adatoms are deposited onto p-doped PbSnSe, resulting in a downwards-bending of the surface band structure. The dependence of the correlation length of Dirac fermions is investigated by determining the edge state hybridization for pristine and doped (Pb,Sn)Se.
[1] P. Sessi et al., Science 354, 6317 (2016)
[2] J. Jung et al., Phys. Rev. Lett. 126, 236402 (2021)
[3] P. M. Echenique et al., Surf. Sci. Rep. 52, 219 (2004)