Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hole superconductivity in $H_2S$ and other sulfides under high pressure   Superconductivity at temperatures up to 190 K at high pressures has recently
been observed in $H_2S$ and interpreted as conventional
BCS-electron-phonon-driven superconductivity.\cite{h2s} Instead we propose that
it is another example of the mechanism of hole superconductivity at work.
Within this mechanism high temperature superconductivity arises when holes
conduct through negatively charged anions in close proximity. We propose that
electron transfer from $H$ to $S$ leads to conduction by holes in a nearly full
band arising from direct overlap of $S^=$ $p$ orbitals in a planar structure.
The superconductivity is non-phononic and is driven by pairing of heavily
dressed hole carriers to lower their kinetic energy. Possible explanations for
the observed lower critical temperature of $D_2S$ are discussed. We predict
that high temperature superconductivity will also be found in other sulfides
under high pressure such as $Li_2S$, $Na_2S$ and $K_2S$.

35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics