Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Circularly polarized light emission in scanning tunneling microscopy of
  magnetic systems   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 ${\pm}$2 %. We predict
that the use of a silver tip would increase the degree of circular polarization
for a range of photon energies.

15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg