SKM 2021 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 27: Topological Insulators and Semimetals (joint session TT/KFM)

TT 27.2: 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 Bercioux^1,4 — 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.