Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photoemission Evidence for a Remnant Fermi Surface and d-Wave-Like
  Dispersion in Insulating Ca2CuO2Cl2   An angle resolved photoemission study on Ca2CuO2Cl2, a parent compound of
high Tc superconductors is reported. Analysis of the electron occupation
probability, n(k) from the spectra shows a steep drop in spectral intensity
across a contour that is close to the Fermi surface predicted by the band
calculation. This analysis reveals a Fermi surface remnant even though
Ca2CuO2Cl2 is a Mott insulator. The lowest energy peak exhibits a dispersion
with approximately the |cos(kxa)-cos(kya)| form along this remnant Fermi
surface. Together with the data from Dy doped Bi2Sr2CaCu2O(8 + delta) these
results suggest that this d-wave like dispersion of the insulator is the
underlying reason for the pseudo gap in the underdoped regime.

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The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
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The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph
19
The categories of this paper are: eess
6
The categories of this paper are: astro-ph