Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Basic physics of solid materials   Since the cuprate materials behave many curious properties, the mechanism
that causes high-temperature superconductivity in copper oxide materials
(cuprates) has been a controversial topic. To explain these curious properties,
we must look out the physics what these materials include. In this letter, it
is presented that there are the basic physics (1)-(9) in solid materials. I
divide all solid materials into four categories, explain some properties of
them qualitatively, and suggest some ways to turn a solid material into a
superconductor. Particularly, this letter discusses the differences between the
p-type high-Tc cuprate superconductors, the n-type superconductor Nd2-xCexCuO4,
the BCS-superconductor similar MgB2, and heavy Fermions superconductors.

12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat