Freiburg 2019 – wissenschaftliches Programm
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FM: Fall Meeting
FM 10: Topology: Artificial Systems
FM 10.2: Talk
Montag, 23. September 2019, 14:30–14:45, 1199
Topologically Protected Giant End Spins in Carbon Nanotubes — •Gergely Zarand1, Pascu Moca1,2, Wataru Izumida3, Balazs Dora4, and Örs Legeza5 — 1BME-MTA Exotic Quantum Phases Research Group, Institute of Physics, Budapest University of Technology and Economics, Hungary — 2Department of Physics, University of Oradea, Romania — 3Department of Physics, Tohoku University, Sendai, Japan — 4Department of Theoretical Physics and MTA-BME Lendulet Topology and Correlation Research Group, Budapest University of Technology and Economics, Hungary — 5Strongly Correlated Systems Lendület Research group, Wigner Research Centre for Physics, Budapest, Hungary
Carbon nanotubes can be classified according to topological classes. For most chiralities, semiconducting nanotubes display topologically protected end states of multiple degeneracies. We study these end states in the presence of Coulomb interactions by means of DMRG-based quantum chemistry tools and demonstrate the formation of giant end spins, the close analogues of ferromagnetic states emerging at graphene nanoribbon edges. The interaction between the two ends is sensitive to the length of the nanotube, its dielectric constant, as well as the size of the end spins: for S=1/2 end spins their interaction is antiferromagnetic, while for S>1/2 it changes from antiferromagnetic to ferromagnetic with increasing nanotube length. The interaction between end spins can be designed by controlling the dielectric constant of the environment, thereby providing a possible platform for two-spin quantum manipulations.