Large 2D Coulomb crystals in a radio frequency surface ion trap
  We designed and operated a surface ion trap, with an ion-substrate distance of 500\mum, realized with standard printed-circuit-board techniques. The trap has been loaded with up to a few thousand Sr+ ions in the Coulomb-crystal regime. An analytical model of the pseudo-potential allowed us to determine the parameters that drive the trap into anisotropic regimes in which we obtain large (N>150) purely 2D ion Coulomb crystals. These crystals may open a simple and reliable way to experiments on quantum simulations of large 2D systems. 
B. Szymanski and R. Dubessy and B. Dubost and S. Guibal and J.-P.   Likforman and L. Guidoni
quant-ph physics.atom-ph