2000/01/05 by S. P. Apell, D. R. Penn, P. Johansson
Physics and Astronomy · #cond-mat
paper · pdf · doi:10.1103/physrevb.61.3534
published as Phys. Rev. B 61, 3534 (2000). · 15 pages, 4 figures, (To appear in Phys. Rev. B, February 2000)
arxiv created 2000/01/05 · arxiv updated 2009/11/30
Light is produced when a scanning tunneling microscope is used to probe a metal surface. Recent experiments on cobalt utilizing a tungsten tip found that the light is circularly polarized; the sense of circular polarization depends on the direction of the sample magnetization, and the degree of polarization is of order 10 %. This raises the possibility of constructing a magnetic microscope with very good spatial resolution. We present a theory of this effect for iron and cobalt and find a degree of polarization of order 0.1 %. This is in disagreement with the experiments on cobalt as well as previous theoretical work which found order of magnitude agreement with the experimental results. However, a recent experiment on iron showed 0.0 ±2 %. We predict that the use of a silver tip would increase the degree of circular polarization for a range of photon energies.