Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Metastability of NbN in the ordered vacancy NbO phase   A metastable phase of NbN with superconducting Tc=16.4 K was reported
recently by Treece and collaborators. The reported structure of the thin film
sample deviates from the rocksalt (B1) NbN structure with 25% ordered vacancies
on each sublattice (space group Pm3m) and a lattice constant of 4.442
Angstroms. Using full potential electronic structure methods, we contrast the
electronic structure with that of B1 NbN. The calculated energy, 1.00
eV/molecule higher than B1 NbN, and calculated lattice constant of 4.214
Angstroms indicate that the new phase must be something other than the ordered
stoichiometric Pm3m phase.

1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn