Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Defects responsible for abnormal n-type conductivity in Ag-excess doped
  PbTe thermoelectrics   We find that Ag-interstitial ($Ag_I$) acts as an electron donor and plays an
important role in Ag-excess doped polycrystalline PbTe thermoelectric
materials. When Ag is heavily doped in PbTe, the neutral (Ag-Ag) dimer defect
is formed at the Pb-site and the environment becomes Pb-rich/Te-poor condition.
Then the positively ionized Ag interstitial ($Ag_I^+$) defect becomes the major
defect under Pb-rich condition. Due to the small formation energy and small
diffusion barrier of $Ag_I^+$, Ag can be easily dissolved into the PbTe matrix.
The temperature behavior of the Ag defect formation energy well explains the
$Ag_I^+$ solubility, the electron carrier generation, and the increasing
electrical conductivity in Ag-excess doped polycrystalline PbTe at high
temperature. This abnormal doping behavior by forming interstitial defects is
also found for Au-doped PbTe.

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The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
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The categories of this paper are: eess
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg