Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Structural and electronic phase transitions in Zr$_{1.03}$Se$_{2}$ at
  high pressure   A detailed high pressure investigation is carried out using x-ray
diffraction, Raman spectroscopy and low temperature resistivity measurements on
hexagonal ZrSe$_{2}$ having an excess of 3 at.\% Zr. Structural studies show
that the sample goes through a gradual structural transition from hexagonal to
monoclinic phase, with a mixed phase in the pressure range 5.9 GPa to 14.8 GPa.
Presence of a minimum in the $c/a$ ratio in the hexagonal phase and a minimum
in the full width half maximum of the $A_{1g}$ mode at about the same pressure
indicates an electronic phase transition. The sample shows a metallic
characteristic in its low temperature resistivity data at ambient pressure,
which persist till about 5.1 GPa and can be related the presence of slight
excess Zr. At and above 7.3 GPa, the sample shows a metal to semiconductor
transition with the opening of a very small band gap, which increases with
pressure. The low temperature resistivity data show an upturn, which flattens
with an increase in pressure. The phenomenological analysis of the low
temperature resistivity data indicates the presence of Kondo effect in the
sample, which may be due to the excess Zr.

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The categories of this paper are: astro-ph
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The categories of this paper are: eess
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
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The categories of this paper are: hep-ph
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat