Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of the Electronic Structures of Two Non-cuprate Layered
  Transition Metal Oxide Superconductors   Comparison is made of the electronic structure of the little-studied layered
transition metal oxide LiNbO$_2$ with that of Na$_x$CoO$_2$, which has
attracted tremendous interest since superconductivity was discovered in its
hydrate. Although the active transition metal $d$ states are quite different
due to different crystal fields and band filling, both systems show a strong
change of electronic structure with changes in the distance between the
transition metal ion layer and the oxygen layers. The niobate is unusual in
having a large second-neighbor hopping amplitude, and a nearest neighbor
hopping amplitude that is sensitive to the Nb-O separation. Li$_x$NbO$_2$ also
presents the attractive simplicity of a single band triangular lattice system
with variable carrier concentration that is superconducting.

22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc