Trapping Fermionic 40K and Bosonic 87Rb on a Chip

We demonstrate the loading of a Bose–Fermi mixture into a microfabricated magnetic trap. In a single-chamber vacuum system, laser-cooled atoms are transported to the surface of a substrate on which gold wires have been microfabricated. The magnetic field minimum formed near these current-carrying wires is used to confine up to 6 × 104 neutral 40K atoms. In addition, we can simultaneously load 2 × 105 87Rb atoms, demonstrating the confinement of two distinct elements with such a trap. In a sequence optimized for 87Rb alone, we observe up to 1 × 107 trapped atoms. We describe in detail the experimental apparatus, and discuss prospects for evaporative cooling towards quantum degeneracy in both species.