Tight-binding theory of the spin-orbit coupling in graphene structures

By S. Konschuh, M. Gmitra, Jaroslav Fabian. 2010

333 citations recorded by the source corpus.

The spin-orbit coupling in graphene induces spectral gaps at the high-symmetry points. The relevant gap at the Γ point is similar to the splitting of the p orbitals in the carbon atom, being roughly 8.5 meV. The splitting at the K point is orders of magnitude smaller. Earlier tight-binding theories indicated the value of this intrinsic gap of 1 μeV, based on the σ−π coupling. All-electron first-principles calculations give much higher values, between 25 and 50 μeV, due to the presence of the orbitals of the d symmetry in the Bloch states at K. A realistic multiband tight-binding model is presented to explain the effects the d orbitals play in the spin-orbit coupling at K. The π−σ coupling is found irrelevant to the value of the intrinsic spin-orbit-induced gap. On the other hand, the extrinsic spin-orbit coupling (of the Bychkov-Rashba type), appearing in the presence of a transverse electric field, is dominated by the π−σ hybridization, in agreement with previous theories. Tight-binding parameters are obtained by fitting to first-principles calculations, which also provide qualitative support for the model when considering the trends in the spin-orbit-induced gap in graphene under strain. Finally, an effective single-orbital next-nearest-neighbor hopping model accounting for the spin-orbit effects is derived.

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

View Paper: https://www.semanticscholar.org/paper/1d06ffb97792ac678607bdd7428b95df94886ad6

How researchers see this paper

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

In Materials Chemistry

  1. A. Huczko
  2. Ramesh Oraon
  3. V. Kumar
  4. G. C. Nayak
  5. A. Adhikari
  6. S. Tiwari

Citations in the corpus