Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Doping evolution of the phonon density of states and electron-lattice
  interaction in Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$   We use inelastic neutron scattering to study the evolution of the generalized
phonon density of states (GDOS) of the $n$-type high-$T_c$ superconductor
Nd$_{2-x}$Ce$_x$CuO$_{4+\delta}$ (NCCO), from the half-filled Mott-insulator
($x=0$) to the $T_c=24$ K superconductor ($x=0.15$). Upon doping the CuO$_2$
planes in Nd$_2$CuO$_{4+\delta}$ (NCO) with electrons by Ce substitution, the
most significant change in the GDOS is the softening of the highest phonon
branches associated with the Cu-O bond stretching and out-of-plane oxygen
vibration modes. However, the softening occurs within the first few percent of
Ce-doping and is not related to the electron doping induced
nonsuperconducting-superconducting transition (NST) at $x\approx 0.12$. These
results suggest that the electron-lattice coupling in the $n$-type high-$T_c$
superconductors is different from that in the $p$-type materials.

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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: quant-ph