Regensburg 2019 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Focus Session: Designer Quantum Systems II (joint session O/TT)
TT 32.1: Hauptvortrag
Dienstag, 2. April 2019, 14:00–14:30, H15
Topological quantum phases in atomically precise graphene nanoribbons — •Oliver Gröning1, Shiyong Wang2, Qiang Sun1, Akimitsu Narita3, Müllen Klaus3, Pascal Ruffieux1, and Roman Fasel1 — 1Empa Materials Science and Technology, Dübendorf, Switzerland — 2School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China — 3Max Planck Institute for Polymer Research, Mainz, Germany
Topological materials have attracted great interest in solid state physics due to their ability to support robust, yet exotic quantum states at their boundaries or interfaces such as spin-momentum locked transport channels or Majorana fermions. Very recently, it has been found theoretically by Louie et al., that localized zero energy modes can be obtained at the junctions of topologically dissimilar graphene nanoribbons (GNR). We have experimentally realized such GNR junctions using on-surface synthesis, i.e. by the polymerization of molecular precursors rationally designed to yield the desired final GNR on single crystal surfaces. By creating well defined periodic sequences of these topological electronic modes, one-dimensional electronic bands can be created, which are described by the Su-Schrieffer-Heeger (SSH) Hamiltonian representing the dimerized atomic chain. By manipulating the intra- and inter-cell coupling strength we could further create SSH analogs with different winding number and therefore topological class. The topological class distinction is evidenced by presence, respectively absence of zero energy end states at the termini of the corresponding GNR or their junctions to structurally dissimilar GNRs.