Local atomic strain in ZnSe1-xTex from high real-space resolution neutron pair distribution function measurements - art. no. 165211

High real-space resolution atomic pair distribution functions (PDF's) have been obtained from ZnSe1-xTex using neutron powder diffraction. Distinct Zn -Se and Zn-Te nearest-neighbor (nn) bonds, differing in length by Deltar = 0.14 Angstrom, are resolved in the measured PDF's, allowing the evolution w ith composition of the individual bond lengths to be studied. The local bon d lengths change much more slowly with doping than the average bond length obtained crystallographically. The nn bond-length distributions are constan t with doping, but higher-neighbor pair distributions broaden significantly , indicating that most of the strain from the alloying is accommodated by b ond-bending forces in the alloy. PDF's of alloys across the whole doping ra nge are well fit using a model based on the Kirkwood potential. The resulti ng PDF's give excellent agreement with the measured PDF's over the entire a lloy range with no adjustable parameters.