A recent paper in Science made the claim of 92% polarization for the injection spin polarized electrons from a Ni scanning tunneling microscopy (STM) tip into GaAs(110). Actually they state their result as 92% efficiency for the injection of 100% importance for the emerging field of Spintronics. If true, it would suggest that the field is rapidly closing in on the key goal of 100% efficiency. However, we wish to inform the Science readership that the claim is by no means substantiated by a close examination of the work, and in fact serious errors in the analysis imply that the actual polarization was much less than 92%. Since the tip is not 100% spin polarized, it makes no sense to break this polarization into a tip polarization times an efficiency.
Issue: No. 5571
Pub Type: Journals
gallium arsnide tunneling nickel, spin polarization