CNR Institutional Research Information System

EXAFS and negative thermal expansion in CdTe

F Rocca;
2009
2009
Istituto di fotonica e nanotecnologie - IFN
SILS 2009 - XVII Convegno della Società Italiana di Luce di Sincrotrone.
No
Camerino MC (Italy) 24-26 Jul
Abstract: CdTe has the zincblende structure and is affected by a negative thermal expansion (NTE) of the lattice parameter below about 70 K. The NTE strength and temperature interval in CdTe are intermediate between those of Ge and CuCl. Temperature dependent EXAFS measurements have been performed on CdTe, to study its local dynamical properties and compare them with those of other diamond-zincbende NTE semicondutors. The cumulant analysis of the first-shell contribution to EXAFS has shown that the bond thermal expansion is positive within the full explored temperature range, 20 to 300 K, like for all other NTE materials studied by EXAFS up to now. The perpendicular MSRD has been obtained from the difference between bond and lattice thermal expansions. The effective force constants obtained by fitting Einstein models to the temperature dependence of the parallel and perpendicular MSRDs are 3.76 and 0.9 eV/Å2, respectively. The values of these force constants, as well as the ratio of perpendicular to parallel MSRD, which measures the anisotropy of relative vibrations, are intermediate between the values previously found for Ge and CuCl. A qualitative correlation can be established between local dynamical quantities measured by EXAFS and NTE properties.
1
none
N. Abd el All; G. Dalba; D. Diop; P. Fornasini; R. Grisenti; F. Rocca; B. Thiodjio Sendja;M. Vaccari
273
info:eu-repo/semantics/conferenceObject
04 Contributo in convegno::04.01 Contributo in Atti di convegno
04.01 Contributo in Atti di convegno
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/80015
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