Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tuning the electronic states and superconductivity in alkali fulleride
  films   The successful preparation of superconducting alkali fulleride
(A$_x$C$_{60}$, A = K, Rb, Cs) films using state-of-the-art molecular beam
epitaxy overcomes the disadvantages of the air-sensitivity and phase separation
in bulk A$_x$C$_{60}$, enabling for the first time a direct investigation of
the superconductivity in alkali fullerides on the molecular scale. In this
paper, we briefly review recent cryogenic scanning tunneling microscopy results
of the structural, electronic, and superconducting properties of the fcc
A$_x$C$_{60}$ films grown on graphitized SiC substrates. Robust $s$-wave
superconductivity is revealed against the pseudogap, electronic correlation,
non-magnetic impurities, and merohedral disorder. By controlling the alkali
metal species, film thickness, and electron doping, we systematically tune the
C$_{60}^{x-}$ orientational orderings and superconductivity in A$_x$C$_{60}$
films and then complete a unified phase diagram of superconducting gap size vs
electronic correlation and doping. These investigations are conclusive and
elucidated that the $s$-wave superconductivity retains in alkali fullerides
despite of the electronic correlation and presence of pseudogap.

1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol