Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase coexistence and metal-insulator transition in few-layer
  phosphorene: A computational study   Based on {\em ab initio} density functional calculations, we propose
$\gamma$-P and $\delta$-P as two additional stable structural phases of layered
phosphorus besides the layered $\alpha$-P (black) and $\beta$-P (blue)
phosphorus allotropes. Monolayers of some of these allotropes have a wide band
gap, whereas others, including $\gamma$-P, show a metal-insulator transition
caused by in-layer strain or changing the number of layers. An unforeseen
benefit is the possibility to connect different structural phases at no energy
cost. This becomes particularly valuable in assembling heterostructures with
well-defined metallic and semiconducting regions in one contiguous layer.

34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an