Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Towards understanding the special stability of
  ${\text{SrCo}\text{O}_{2.5}}$ and ${\text{HSrCo}\text{O}_{2.5}}$   Reversible hydrogen incorporation was recently attested [N. Lu, $\textit{et
al.}$, Nature $\textbf{546}$, 124 (2017)] in ${\text{SrCo}\text{O}_{2.5}}$, the
brownmillerite phase (BM) of strontium cobalt oxide (SCO), opening new avenues
in catalysis and energy applications. However, existing theoretical studies of
BM-SCO are insufficient, and that of ${\text{HSrCo}\text{O}_{2.5}}$, the
newly-reported hydrogenated SCO (H-SCO), is especially scarce. In this work, we
demonstrate how the electron-counting model (ECM) can be used in understanding
the phases, particularly in explaining the stability of the oxygen-vacancy
channels (OVCs), and in examining the Co valance problem. Using
density-functional theoretical (DFT) methods, we analyze the crystalline,
electronic, and magnetic structures of BM- and H-SCO. Based on our structure
search, we discovered stable phases with large bandgaps (> 1 eV) for both
BM-SCO and H-SCO, agreeing better with experiments on the electronic
structures. Our calculations also indicate limited charge transfer from H to O
that may explain the special stability of the H-SCO phase and the reversibility
of H incorporation observed in experiments. In contrary to the initial study,
our calculation also suggests intrinsic antiferromagnetism (AFM) of H-SCO,
showing how the measured ferromagnetism (FM) has possible roots in hole doping.

20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph