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TT: Fachverband Tiefe Temperaturen
TT 41: Topological Semimetals
TT 41.9: Vortrag
Mittwoch, 11. März 2026, 11:45–12:00, HSZ/0103
End spin formation in capped carbon nanotubes — •István Markó1, Dominik Szombathy1,2, Cătălin P. Moca4,2, and Gergely Zaránd1,3 — 1Budapest University of Technology and Economics, Budapest, Hungary — 2Nokia Bell Labs Budapest site, Hungary — 3HUN-REN–BME Quantum Dynamics and Correlations, Budapest, Hungary — 4University of Oradea, Oradea, Romania
Semiconducting open carbon nanotubes (CNTs) have been shown to exhibit topological bound states within the spectral gap [1], giving rise to spin formation at the ends of the nanotube [2]. However, the production of open-ended CNTs is difficult. Here, we investigate the electronic properties of capped topological CNTs using exact diagonalization and Chebyshev expansion methods to identify local resonances and bound states in the density of states at the end of long tubes [3]. While capping removes topological states, non-topological bound states and resonances localized on the pentagons appear, presumably related to Euler topology. We observe an abundance of local resonances and bound states, and about 20% of the investigated stable caps are predicted to produce end spins [4]. We identify a specific CNT of chirality (6,5) which produces well-defined end spins. This type of CNT can be produced with ultra-high purity (>95%) [5], and is an excellent candidate for a geometrically controlled spin qubit.
[1] W. Izumida, et al. Phys. Rev. B 93, 195442 (2016).
[2] C. P. Moca, et al. Phys. Rev. Lett. 125, 056401 (2020).
[3] A. Weiße, et al. Rev. Mod. Phys. 78, 275 (2006).
[4] I. Markó, et al. unpublished
[5] S. Shiina, et al. ACS Nano 18, 23979 (2024)
Keywords: Carbon nanotubes; End spin formation; Topological states; Condensed matter physics; Numerical simulation