Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bi2Te1.6S1.4 - a Topological Insulator in the Tetradymite Family   We describe the crystal growth, crystal structure, and basic electrical
properties of Bi2Te1.6S1.4, which incorporates both S and Te in its Tetradymite
quintuple layers in the motif -[Te0.8S0.2]-Bi-S-Bi-[Te0.8S0.2]-. This material
differs from other Tetradymites studied as topological insulators due to the
increased ionic character that arises from its significant S content.
Bi2Te1.6S1.4 forms high quality crystals from the melt and is the S-rich limit
of the ternary Bi-Te-S {\gamma}-Tetradymite phase at the melting point. The
native material is n-type with a low resistivity; Sb substitution, with
adjustment of the Te to S ratio, results in a crossover to p-type and resistive
behavior at low temperatures. Angle resolved photoemission study shows that
topological surface states are present, with the Dirac point more exposed than
it is in Bi2Te3 and similar to that seen in Bi2Te2Se. Single crystal structure
determination indicates that the S in the outer chalcogen layers is closer to
the Bi than the Te, and therefore that the layers supporting the surface states
are corrugated on the atomic scale.

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The categories of this paper are: astro-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: math-ph
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th