Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phonon Spectra in the Parent Superconducting Iron-tuned Telluride
  Fe$_{1+x}$Te from Inelastic Neutron Scattering and Ab Initio Calculations   We report inelastic neutron scattering measurements of phonon spectra in the
parent superconductor iron-tuned chalcogenide Fe$_{1+x}$Te, for two different x
contents (x $\leq$ 0.11), using neutron time-of-flight technique. Thermal
neutron spectroscopy allowed to collect the low-temperature Stokes spectra over
an extended Q-range, at 2, 40 and 120K - hence covering both the magnetic
monoclinic and the paramagnetic tetragonal phases. Whereas cold-neutrons
allowed to measure high-resolution anti-Stokes spectra at 140, 220 and 300K,
thus covering the tetragonal phase. Our results evidence a spin-phonon coupling
behaviour towards the observed noticeable temperature-dependent change of the
Stokes spectra across the transition temperatures. On the other hand, the
anti-Stokes spectra reveal a pronounced hardening of the low-energy, acoustic
region, of the phonon spectrum, upon heating, indicating a strong anharmonicity
and a subtle dependence of phonons on structural evolution within the
tetragonal phase. Experimental results are accompanied by ab initio
calculations of phonon spectra of the tetragonal stoichiometric phase for a
comparison with the high-resolution anti-Stokes spectra. Calculations included
different density functional methods. Spin polarization and van der Waals
interaction, were either considered or neglected, individually or
concomitantly, in order to study their respective effect on lattice dynamics
description. Our results suggest that including van der Waals interaction has
only a slight effect on phonon dynamics, however, phonon spectra are better
described when spin polarization is included, in a cooperative way with van der
Waals interactions.

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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: econ
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The categories of this paper are: gr-qc
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th