Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superconductivity at 5 K in potassium doped phenanthrene   Organic materials are believed to be potential superconductor with high
transition temperature (TC). Organic superconductors mainly have two families:
the quasi-one dimensional (TMTSF)2X and two dimensional (BEDT-TTF)2X (Ref. 1
and 2), in which TMTSF is tetramethyltetraselenafulvalene (C10H12Se4) and
BEDT-TTF or "ET" is bis(ethylenedithio)tetrathiafulvalene (C10H8S8). One key
feature of the organic superconductors is that they have {\pi}-molecular
orbitals, and the {\pi}-electron can delocalize throughout the crystal giving
rise to metallic conductivity due to a {\pi}-orbital overlap between adjacent
molecules. The introduction of charge into C60 solids and graphites with
{\pi}-electron networks by doping to realize superconductivity has been
extensively reported3,4. Very recently, superconductivity in alkali-metal doped
picene with {\pi}-electron networks was reported5. Here we report the discovery
of superconductivity in potassium doped Phenanthrene with TC~5 K. TC increases
with increasing pressure, and the pressure of 1 GPa leads to an increase of 20%
in TC, suggesting that the potassium doped phenanthrene shows unconventional
superconductivity. Both phenanthrene and picene are polycyclic aromatic
hydrocarbons, and contain three and five fused benzene rings, respectively. The
ribbon of fused benzene rings is part of graphene. Therefore, the discovery of
superconductivity in K3Phenanthrene produces a novel broad class of
superconductors consisting of fused hydrocarbon benzene rings with
{\pi}-electron networks. The fact that TC increases from 5 K for KxPhenanthrene
with three benzene rings to 18 K for Kxpicene with five benzene rings suggests
that such organic hydrocarbons with long benzene rings is potential
superconductor with high TC.

1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga