High real-space resolution atomic pair distribution functions (PDFs) have
been obtained from ZnSe(1-x)Te(x) using neutron powder diffraction. Distinct
Zn-Se and Zn-Te nearest neighbor (nn) bonds, differing in length by delta_r=
0.14Angstroms, are resolved in the measured PDF allowing the evolution with
composition of the individual bond-lengths to be studied. The local
bond-lengths change much more slowly with doping than the average bond-length
obtained crystallographically. The nn bond-length distributions are constant
with doping but higher-neighbor pair distributions broaden significantly
indicating that most of the strain from the alloying is accommodated by
bond-bending forces in the alloy. The PDFs of alloys across the whole doping
range are well fit using a model based on the Kirkwood potential. The resulting
PDFs give excellent agreement with the measured PDFs over the entire alloy
range with no adjustable parameters.
cond-mat.mtrl-sci
,cond-mat.mtrl-sci
