Structural and vibrational study of the negative thermal expansion in liquid As2Te3

Autor: Otjacques, C., Raty, J. Y., Hippert, F., Schober, H., Johnson, M., Ceolin, R., Gaspard, J. P.
Přispěvatelé: Laboratoire des matériaux et du génie physique (LMGP ), Institut National Polytechnique de Grenoble (INPG)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Departament de Fisica i Enginyeria Nuclear (ETSEIB), Universitat Politècnica de Catalunya [Barcelona] (UPC)
Jazyk: angličtina
Rok vydání: 2010
Předmět:
Zdroj: Physical Review B: Condensed Matter and Materials Physics (1998-2015)
Physical Review B: Condensed Matter and Materials Physics (1998-2015), American Physical Society, 2010, 82 (5), pp.054202. ⟨10.1103/PhysRevB.82.054202⟩
ISSN: 1098-0121
1550-235X
DOI: 10.1103/PhysRevB.82.054202⟩
Popis: International audience; We present an experimental and theoretical study of liquid As2Te3. This alloy exhibits a negative thermal expansion (NTE) in a 250 K range above the melting temperature T-m=654 K. We evidence the changes in As2Te3 structure by measuring neutron-diffraction spectra at five temperatures in the NTE range and perform first principles molecular dynamics simulations at the same temperatures and densities to study the local order evolution in the liquid. Our calculated structures show an increase in the coordination numbers and a symmetrization of the first neighbors shell around atoms when the temperature rises. To confirm these results, we performed inelastic neutron scattering to obtain the vibrational density of state (VDOS) along the NTE. We see a clear change in the VDOS, consisting in a redshift of the highest frequencies with temperature. Finally, electrical conductivity evolution was obtained from the simulated structures, to compare with the semiconductor to metal transition measured experimentally.
Databáze: OpenAIRE
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