Synthetic 3D Spin-Orbit Coupling
  We describe a method for creating a three-dimensional analogue to Rashba spin-orbit coupling in systems of ultracold atoms. This laser induced coupling uses Raman transitions to link four internal atomic states with a tetrahedral geometry, and gives rise to a Dirac point that is robust against environmental perturbations. We present an exact result showing that such a spin-orbit coupling in a fermionic system always rise to a molecular bound state. 
Brandon M. Anderson and Gediminas Juzeli\=unas and Ian B. Spielman and   Victor M. Galitski
cond-mat.quant-gas