Coupling of Spin and Orbital Motion of Electrons in Carbon Nanotubes

dc.creatorKuemmeth, F.
dc.creatorIlani, S.
dc.creatorRalph, D. C.
dc.creatorMcEuen, P. L.
dc.date2008-02-10
dc.date.accessioned2026-07-07T09:30:22Z
dc.date.available2026-07-07T09:30:22Z
dc.descriptionElectrons in atoms possess both spin and orbital degrees of freedom. In non-relativistic quantum mechanics, these are independent, resulting in large degeneracies in atomic spectra. However, relativistic effects couple the spin and orbital motion leading to the well-known fine structure in their spectra. The electronic states in defect-free carbon nanotubes (NTs) are widely believed to be four-fold degenerate, due to independent spin and orbital symmetries, and to also possess electron-hole symmetry. Here we report measurements demonstrating that in clean NTs the spin and orbital motion of electrons are coupled, thereby breaking all of these symmetries. This spin-orbit coupling is directly observed as a splitting of the four-fold degeneracy of a single electron in ultra-clean quantum dots. The coupling favours parallel alignment of the orbital and spin magnetic moments for electrons and anti-parallel alignment for holes. Our measurements are consistent with recent theories that predict the existence of spin-orbit coupling in curved graphene and describe it as a spin-dependent topological phase in NTs. Our findings have important implications for spin-based applications in carbon-based systems, entailing new design principles for the realization of qubits in NTs and providing a mechanism for all-electrical control of spins in NTs.
dc.description14 pages, 6 figures
dc.identifierhttps://arxiv.org/abs/0802.1351
dc.identifierhttp://arxiv.org/abs/0802.1351
dc.identifierNature 452, 448-452 (27 March 2008)
dc.identifierdoi:10.1038/nature06822
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/158103
dc.subjectMesoscale and Nanoscale Physics
dc.titleCoupling of Spin and Orbital Motion of Electrons in Carbon Nanotubes
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