Spin-orbit coupling in curved graphene, fullerenes, nanotubes, and nanotube caps

By D. Huertas-Hernando, Francisco Guinea, A. Brataas. 2006

739 citations recorded by the source corpus.

A continuum model for the effective spin-orbit interaction in graphene is derived from a tight-binding model which includes the $\ensuremath{\pi}$ and $\ensuremath{\sigma}$ bands. We analyze the combined effects of the intra-atomic spin-orbit coupling, curvature, and applied electric field, using perturbation theory. We recover the effective spin-orbit Hamiltonian derived recently from group theoretical arguments by Kane and Mele. We find, for flat graphene, that the intrinsic spin-orbit coupling ${\ensuremath{\Delta}}_{\mathrm{int}}\ensuremath{\propto}{\ensuremath{\Delta}}^{2}$ and the Rashba coupling due to a perpendicular electric field $\mathcal{E}$, ${\ensuremath{\Delta}}_{\mathcal{E}}\ensuremath{\propto}\ensuremath{\Delta}$, where $\ensuremath{\Delta}$ is the intra-atomic spin-orbit coupling constant for carbon. Moreover we show that local curvature of the graphene sheet induces an extra spin-orbit coupling term ${\ensuremath{\Delta}}_{\mathrm{curv}}\ensuremath{\propto}\ensuremath{\Delta}$. For the values of $\mathcal{E}$ and curvature profile reported in actual samples of graphene, we find that ${\ensuremath{\Delta}}_{\mathrm{int}}l{\ensuremath{\Delta}}_{\mathcal{E}}\ensuremath{\lesssim}{\ensuremath{\Delta}}_{\mathrm{curv}}$. The effect of spin-orbit coupling on derived materials of graphenelike fullerenes, nanotubes, and nanotube caps, is also studied. For fullerenes, only ${\ensuremath{\Delta}}_{\mathrm{int}}$ is important. Both for nanotubes and nanotube caps ${\ensuremath{\Delta}}_{\mathrm{curv}}$ is in the order of a few Kelvins. We reproduce the known appearance of a gap and spin-splitting in the energy spectrum of nanotubes due to the spin-orbit coupling. For nanotube caps, spin-orbit coupling causes spin-splitting of the localized states at the cap, which could allow spin-dependent field-effect emission.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/bd190ff876773867f0a55e91013d43ef96b3856e

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The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

  1. N. M. R. Peres
  2. K. Novoselov
  3. E. Hwang
  4. E. Rossi
  5. S. Adam
  6. Francisco Guinea
  7. A.K. Geim
  8. A. C. Castro Neto

In Materials Chemistry

  1. N. M. R. Peres
  2. K. Novoselov
  3. E. Hwang
  4. Francisco Guinea
  5. E. Rossi
  6. S. Adam
  7. A. C. Castro Neto
  8. A.K. Geim

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