Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Carbon Nanotube Based Magnetic Tunnel Junctions   Spin-coherent quantum transport in carbon nanotube magnetic tunnel junctions
was investigated theoretically. A spin-valve effect is found for metallic,
armchair tubes, with a magneto-conductance ratio ranging up to 20%. Because of
the finite length of the nanotube junctions, transport is dominated by resonant
transmission. The magnetic tunnel junctions are found to have distinctly
different transport behavior depending on whether or not the length of the
tubes is commensurate with a 3N+1 rule, with N the number of basic carbon
repeat units along the nanotube length.

28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph