Sub-micron period lattice structures of magnetic microtraps for   ultracold atoms on an atom chip
  We report on the design, fabrication and characterization of magnetic nanostructures to create a lattice of magnetic traps with sub--micron period for trapping ultracold atoms. These magnetic nanostructures were fabricated by patterning a Co/Pd multilayered magnetic film grown on a silicon substrate using high precision e-beam lithography and reactive ion etching. The Co/Pd film was chosen for its small grain size and high remanent magnetization and coercivity. The fabricated structures are designed to magnetically trap $^{87}$Rb atoms above the surface of the magnetic film with 1D and 2D (triangular and square) lattice geometries and sub-micron period. Such magnetic lattices can be used for quantum tunneling and quantum simulation experiments, including using geometries and periods that may be inaccessible with optical lattice. 
I. Herrera, Y. Wang, P. Michaux, D. Nissen, P. Surendran, S.   Juodkazis, S. Whitlock, R. J. McLean, A. Sidorov, M. Albrecht...
cond-mat.quant-gas cond-mat.mes-hall physics.atom-ph