Spin-orbit coupling and optical spin Hall effect in photonic graphene
  We study the spin-orbit coupling induced by the splitting between TE and TM optical modes in a photonic honeycomb lattice. Using a tight-binding approach, we calculate analytically the band structure. Close to the Dirac point,we derive an effective Hamiltonian. We find that the local reduced symmetry ($\mathrm{D_{3h}}$) transforms the TE-TM effective magnetic field into an emergent field with a Dresselhaus symmetry. As a result, particles become massive, but no gap opens. The emergent field symmetry is revealed by the optical spin Hall effect. 
A.V. Nalitov, G. Malpuech, H. Ter\c{c}as, D. Solnyshkov
cond-mat.mes-hall physics.optics