Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chemical pressure effect on superconductivity of BiS2-based
  Ce1-xNdxO1-yFyBiS2 and Nd1-zSmzO1-yFyBiS2   We have systematically investigated the crystal structure and the magnetic
properties of BiS2-based superconductor Ce1-xNdxO1-yFyBiS2 (x = 0 - 1.0, y =
0.3, 0.5 and 0.7) and Nd1-zSmzO1-yFyBiS2 (x = 0 - 0.8, y = 0.3, 0.5 and 0.7).
In the REOBiS2 system, both crystal structure and physical properties are
tunable by mixing the RE (RE = rare earth) site with Ce, Nd and Sm due to the
difference of ionic radius of RE. In the Ce1-xNdxO1-yFyBiS2 system, bulk
superconductivity is observed for x = 1.0 with y = 0.3 and x = 0.5 - 1.0 with y
= 0.5. The transition temperature (Tc) increases with increasing Nd
concentration. The highest Tc is 4.8 K for x = 1.0 with y = 0.5 in the
Ce1-xNdxO1-yFyBiS2 system. By the Nd substitution for Ce, lattice contraction
along the a axis is generated while the c axis does not show a remarkable
dependence on Nd concentration. The lattice constant of c decreases with
increasing F concentration. Furthermore, we found that the Nd site can be
replaced by smaller Sm ions up to z = 0.8 in Nd1-zSmzO1-yFyBiS2. Bulk
superconductivity is observed within z = 0 - 0.8 for y = 0.3 and z = 0 - 0.6
for y = 0.5. The Tc increases with increasing Sm concentration. The highest Tc
is 5.6 K for z = 0.8 with y = 0.3. With increasing Sm concentration, the
lattice constant of a decreases while the lattice constants of c does not show
a remarkable dependence on Sm concentration. We found that the chemical
pressure generated by systematic solution of the RE site in the blocking layer
commonly induces lattice contraction along the a axis in Ce1-xNdxO1-yFyBiS2 and
Nd1-zSmzO1-yFyBiS2. The obtained results indicate that both optimal F
concentration and uniaxial lattice contraction along the a axis generated by
chemical pressure are essential for the inducement of bulk superconductivity in
the REO1-yFyBiS2 system.

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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: hep-th
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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The categories of this paper are: econ
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The categories of this paper are: math-ph