Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic Silicon Fullerene   A metal-encapsulating silicon fullerene, Eu@Si20, has been predicted by
density functional theory to be by far the most stable fullerene-like silicon
structure. The Eu@Si20 structure is a dodecahedron with D2h symmetry in which
the europium atom occupies the center site. The calculated results show that
the europium atom has a large magnetic moment of nearly 7.0 Bohr magnetons. In
addition, it was found that a stable "pearl necklace" nanowire, constructed by
concatenating a series of Eu@Si20 units, with the central europium atom,
retains the high spin moment. The magnetic structure of the nanowire indicates
potential applications in the fields of spintronics and high-density magnetic
storage.

35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom