Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fermi Surface Evolution in an Electron-Doped High-Tc Superconductor
  Revealed by Magnetic Quantum Oscillations   We report on the direct probing of the Fermi surface in the bulk of the
electron-doped superconductor Nd$_{2-x}$Ce$_x$CuO$_4$ at different doping
levels by means of magnetoresistance quantum oscillations. Our data reveal a
sharp qualitative change in the Fermi surface topology, due to translational
symmetry breaking in the electronic system which occurs at a critical doping
level significantly exceeding the optimal doping. This result implies that the
$(\pi/a,\pi/a)$ ordering, known to exist at low doping levels, survives up to
the overdoped superconducting regime.

19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex