Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic Structure, Topological Phase Transitions and
  Superconductivity in (K,Cs)xFe2Se2   We present LDA band structure of novel hole doped high temperature
superconductors (Tc~30K) KxFe2Se2 and CsxFe2Se2 and compare it with previously
studied electronic structure of isostructural FeAs superconductor BaFe2As2
(Ba122). We show that stoichiometric KFe2Se2 and CsFe2Se2 have rather different
Fermi surfaces as compared with Ba122. However at about 60% of hole doping
Fermi surfaces of novel materials closely resemble those of Ba122. In between
these dopings we observe a number of topological Fermi surface transitions near
the G point in the Brillouin zone. Superconducting transition temperature Tc of
new systems is apparently governed by the value of the total density of states
(DOS) at the Fermi level.

18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom