Effect of concentration in Ge-Te liquids: A combined density functional and neutron scattering study

The structural properties of three compositions of Ge-Te liquids (Ge sub(10) Te sub(90), Ge sub(15) Te sub(85), Ge sub(20) Te sub(80)) are studied from a combination of density functional based molecular dynamics simulations and neutron scattering experiments. We investigate structural properties in...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2014-05, Vol.89 (17), Article 174205
Main Authors: Micoulaut, M., Coulet, M.-V., Piarristeguy, A., Johnson, M. R., Cuello, G. J., Bichara, C., Raty, J.-Y., Flores-Ruiz, H., Pradel, A.
Format: Article
Language:English
Subjects:
Condensed Matter
Coordination numbers
Density
Liquids
Materials Science
Molecular structure
Neutron scattering
Physics
Reproduction
Simulation
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Summary:The structural properties of three compositions of Ge-Te liquids (Ge sub(10) Te sub(90), Ge sub(15) Te sub(85), Ge sub(20) Te sub(80)) are studied from a combination of density functional based molecular dynamics simulations and neutron scattering experiments. We investigate structural properties including structure factors, pair distribution functions, angular distributions, coordination numbers, neighbor distributions and compare our results with experimental findings. Most noticeable is the good agreement found in the reproduction of the structure in real and reciprocal space, resulting from the incorporation of dispersion forces in the simulation. This leads to Ge and Te coordination numbers which are lower than in previous studies and which can now be followed with temperature, while also strongly depending on the chosen cutoff distance. Results show a gradual conversion of higher coordinated species (Te super(IV), Ge super(V) ) into lower coordinated ones at lower temperature, while leaving anticipated coordinations from the octet rule (Te super(II) and Ge super(IV)) nearly unchanged. Structural correlations are characterized as a function of temperature and composition. The vibrational density of states is also measured from inelastic neutron scattering for different compositions and temperatures, and compared to the simulated counterpart which exhibits a reasonable agreement at low frequency.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.89.174205