Ai. Lebedev et al., EXAFS studies of the local environment of lead and selenium atoms in PbTe1-xSex solid solutions, PHYS SOL ST, 41(8), 1999, pp. 1275-1282
EXAFS spectroscopy is used to study the local environment of lead and selen
ium atoms in PbTe1-xSex solid solutions. In addition to a bimodal distribut
ion of the bond lengths in the first- coordination sphere, an unusually lar
ge value of the Debye-Waller factors for the Pb-Pb interatomic distances (s
econd-coordination sphere) and a substantial deviation of this value from V
egard's law are observed. Monte Carlo calculations show that these observat
ions are related to the complicated structure of the distribution function
for Pb-Pb distances. It is found that the number of Se-Se pairs in the seco
nd-coordination sphere exceeds the statistical value, which indicates that
chemical factors play an important role in the structure of the solid solut
ions. The contribution of chemical factors to the enthalpy of mixing of the
solid solution is estimated (approximate to 0.5 kcal/mole) and this value
is shown to be comparable to the deformation contribution. (C) 1999 America
n Institute of Physics. [S1063-7834(99)00908-9].