Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cluster structure of superconducting phase and the nature of peaks in
  the doping dependences of the London penetration depth in iron pnictides   The mechanism of formation of dome-like phase diagrams and the features of
magnetic field penetration in iron pnictides with hetero- and isovalent doping
are considered within the framework of the previously proposed model, which
assumes the local character of doping and the cluster structure of resulted
superconducting phase. It is shown that the proposed model, despite its
simplicity and neglect of the features of the electronic structure, makes it
possible not only to accurately calculate the positions of superconducting
domes on the phase diagrams of specific HTSC compounds, but also to explain the
nature and position of sharp peaks in the London penetration depth depending on
the doping level.

14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat