Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Naturally occurring van der Waals materials   The exfoliation of two naturally occurring van der Waals minerals, graphite
and molybdenite, arouse an unprecedented level of interest by the scientific
community and shaped a whole new field of research: 2D materials research.
Several years later, the family of van der Waals materials that can be
exfoliated to isolate 2D materials keeps growing, but most of them are
synthetic. Interestingly, in nature plenty of naturally occurring van der Waals
minerals can be found with a wide range of chemical compositions and crystal
structures whose properties are mostly unexplored so far. This Perspective aims
to provide an overview of different families of van der Waals minerals to
stimulate their exploration in the 2D limit.

17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph