Increasing Spin-Orbital Coupling at Relativistic Exchange Interaction of Electron-Hole Pairs in Graphene

Resumo

Graphene model with a high-energy k · p-Hamiltonian has been proposed. A feature of the model is the increasing spin-orbital coupling at relativistic exchange interactions of electron-hole pairs. Topological nontriviality of the model has been established by non-abelian Zak phase calculations. It has been shown that the homotopy group of the model is Z₂ × Z₄.