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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 13: Topological Insulators and Semimetals (joint session TT/KFM)
KFM 13.2: Talk
Friday, October 1, 2021, 10:15–10:30, H7
Volkov-Pankratov states in topological graphene nanoribbons — Tineke L. van den Berg1, •Alessandro De Martino2, M. Reyes Calvo3, and Dario Bercioux1,4 — 1Donostia International Physics Center, Donostia-San Sebastián, Spain — 2Department of Mathematics, City, University of London, London, United Kingdom — 3Departamento de Fisica Aplicada, Universidad de Alicante, Alicante, Spain — 4IKERBASQUE, Basque Foundation of Science, Bilbao, Spain
In topological systems a smooth modulation of the gap at the interfaces between topologically distinct phases can lead to the appearance of massive edge states, as first described by Volkov and Pankratov in 1985. In this contribution I will show that, in the presence of intrinsic spin-orbit coupling smoothly modulated near the edges, graphene nanoribbons host Volkov-Pankratov states in addition to the topologically protected helical states. This result is obtained by means of two complementary methods, one based on the effective low-energy Dirac equation description and the other on a fully numerical tight-binding approach, with excellent agreement between the two. I will then briefly discuss how transport measurements might reveal the presence of Volkov-Pankratov states, and possible graphene-like structures in which such states might be observed.