Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Breakdown of the coexistence of spin-singlet superconductivity and
  itinerant ferromagnetism   We discuss the possibility of coexistence of spin-singlet superconductivity
and ferromagnetism in a model where the same electrons are assumed responsible
for both of them. Our calculations include both zero and finite momentum
pairing states with both s-wave and d-wave pairing symmetry. Under the
mean-field approximation, the thermodynamic potential of the non-magnetic
superconducting (SC) state is shown to be always lower than that of the
superconducting ferromagnetic (SF) state. It follows that the spin-singlet SF
state is energetically unfavorable, and a spin-triplet SF state is more likely
to survive in metals such as UGe$_{2}$ and ZrZn$_{2}$.

37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci