Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optimizing the Bi_(2-x)Sb_(x)Te_(3-y)Se_(y) solid solutions to approach
  the intrinsic topological insulator regime   To optimize the bulk-insulating behavior in the topological insulator
materials having the tetradymite structure, we have synthesized and
characterized single-crystal samples of Bi_(2-x)Sb_(x)Te_(3-y)Se_(y) (BSTS)
solid solution at various compositions. We have elucidated that there are a
series of "intrinsic" compositions where the acceptors and donors compensate
each other and present a maximally bulk-insulating behavior. At such
compositions, the resistivity can become as large as several Ohmcm at low
temperature and one can infer the role of the surface-transport channel in the
non-linear Hall effect. In particular, the composition of Bi1.5Sb0.5Te1.7Se1.3
achieves the lowest bulk carrier density and appears to be best suited for
surface transport studies.

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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom