Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Elemental Phosphorus: structural and superconducting phase diagram under
  pressure   Pressure-induced superconductivity and structural phase transitions in
phosphorous (P) are studied by resistivity measurements under pressures up to
170 GPa and fully $ab-initio$ crystal structure and superconductivity
calculations up to 350 GPa. Two distinct superconducting transition temperature
(T$_{c}$) vs. pressure ($P$) trends at low pressure have been reported more
than 30 years ago, and for the first time we are able to reproduce them and
devise a consistent explanation founded on thermodynamically metastable phases
of black-phosphorous. Our experimental and theoretical results form a single,
consistent picture which not only provides a clear understanding of elemental P
under pressure but also sheds light on the long-standing and unsolved
$anomalous$ superconductivity trend. Moreover, at higher pressures we predict a
similar scenario of multiple metastable structures which coexist beyond their
thermodynamical stability range. Metastable phases of P experimentally
accessible at pressures above 240 GPa should exhibit T$_{c}$'s as high as 15 K,
i.e. three times larger than the predicted value for the ground-state crystal
structure. We observe that all the metastable structures systematically exhibit
larger transition temperatures than the ground-state ones, indicating that the
exploration of metastable phases represents a promising route to design
materials with improved superconducting properties.

6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an