Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reversible magnetism switching in graphene-based systems via the
  decoration of photochromic molecules   By first principles calculations, we demonstrate that when decorated with
photochromic molecules, it is possible to use light to reversibly control the
magnetic properties of a nanoscale magnetic system. The combination of a
graphene-based magnetic system and a photochromic azobenzene molecule is chosen
as a model system. The {\it trans} and {\it cis} isomers of the azobenzene
molecule that can be converted between each other by means of photoexcitations
are found to have drastically different effects on the magnetic properties of
the system. The results may pave the way for the future design of light
controllable molecular-scale spintronic devices.

8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin