Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evolution of Fermi surface and normal-state gap in chemically
  substituted cuprates Bi$_{2}$Sr$_{2-x}$Bi$_{x}$CuO$_{6+\delta}$   We have performed a systematic angle-resolved photoemission study of
chemically substituted cuprates Bi$_{2}$Sr$_{2-x}$Bi$_{x}$CuO$_{6+\delta}$. We
observed that the Fermi surface area shrinks linearly with Bi substitution
content $x$, reflecting the electron doping nature of this chemical
substitution. In addition, the spectral linewidth broadens rapidly with
increasing $x$, and becomes completely incoherent at the
superconducting-insulating boundary. The d-wave-like normal-state gap observed
in the lightly underdoped region gradually evolves into a large soft gap, which
suppresses antinodal spectral weight linearly in both the excitation energy and
temperature. Combining with the bulk resistivity data obtained on the same
samples, we establish the emergence of the Coulomb gap behavior in the very
underdoped regime. Our results reveal the dual roles, doping and disorder, of
off-plane chemical substitutions in high-$T_c$ cuprates and elucidate the
nature of the quantum electronic states due to strong correlation and disorder.

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The categories of this paper are: mtrl-th
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The categories of this paper are: astro-ph
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: stat
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph