Indication of Complete Spin Filtering in Atomic-Scale Nickel Oxide.

Generating highly spin-polarized currents at the nanoscale is essential for spin current manipulations and spintronic applications. We find indications for up to 100% spin-polarized currents across nickel oxide atomic junctions formed between two nickel electrodes. The degree of spin polarization is probed by analyzing the shot noise resulting from the discrete statistics of spin-polarized electron transport. We show that spin filtering can be significantly enhanced by local chemical modifications at the single-atom level. This approach paves the way for effective manipulations of spin transport at the fundamental limit of miniaturization.