Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Synthesis and transport properties of ternary type-I Si clathrate
  K8Al7Si39   A ternary type-I Si clathrate, K8AlxSi46-x, which is a candidate functional
material composed of abundant non-toxic elements, was synthesized and its
transport properties were investigated at temperatures ranging from 10 to 320
K. The synthesized compound is confirmed to be the ternary type-I Si clathrate
K8Al7Si39 with a lattice parameter of a = 10.442 A using neutron powder
diffractometry and inductively coupled plasma optical emission spectrometry.
Electrical resistivity and Hall coefficient measurements revealed that
K8Al7Si39 is a metal with electrons as the dominant carriers at a density of
approximately 1x10^27 /m3. The value of Seebeck coefficient for K8Al7Si39 is
negative and its absolute value increases with the temperature. The temperature
dependence of the thermal conductivity is similar to that for a crystalline
solid. The dimensionless figure of merit is approximately 0.01 at 300 K, which
is comparable to that for other ternary Si clathrates.

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The categories of this paper are: stat
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
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The categories of this paper are: physics
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin