SEARCH · Engineering Papers

Results for “Cd-Zn”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

3 records

All sources NASA NTRS DOE OSTI

DOE OSTI2025

A first principles study on the adsorbate-adsorbate interactions on the CdTe(111) surface with Cd, Te, Zn, and Se adatoms

The study of adsorbate-adsorbate interactions is essential to understanding early crystal growth dynamics. Here, we employ planewave density functional theory to study the binary adatom pair interactions between Cd-Cd, Te-Te, Zn-Zn, Se-Se, Cd-Te, Cd-Se, Cd-Zn, Te-Se, Te-Zn, and Se-Zn adatom pairs on two CdTe(111) surfaces. An analysis of the interaction energies between binary adatom pairs suggests repulsive interactions are common regardless of the relative distance between adatoms. For the CdTe(111)A surface, attractive interactions occur between neighboring chalcogen (i.e., Te and Se) and Group 12 (i.e., Cd and Zn) adatom pairs. For the CdTe(111)B surface, attractive interactions occur between neighboring Group 12 adatoms forming a surface dimer configuration. Furthermore, the formation energy of an adatom pair is decomposed in terms of the electronic, elastic, and adatom binding contributions. For smaller interatomic distances between the adatoms, the formation energy is primarily a function of the electronic interactions, with null contributions from the elastic and adatom binding interactions for Group 12-containing pairs. Because of the less favorable electronic interactions for larger interatomic distances between the adatoms, the formation energies are typically more positive. Lastly, neighboring adatoms significantly increase the barriers of migration on the CdTe(111)A surface relative to unary adatoms for the top-to-fcc and fcc-to-fcc sites, while the migration barriers on the CdTe(111)B surface only increases for the fcc-to-fcc migration of chalcogen species. From this analysis, we illustrate the role of adatom interactions during the early stages of the surface nucleation processes on CdTe(111) thin films.

CdTe↗

NASA NTRS1973

Chemical composition of Luna 20 rocks and soil and Apollo 16 soils.

Review of the abundances of 24 major, minor, and trace elements measured by instrumental neutron activation analysis in Luna 20 metaigneous rocks, breccia, and soil, and in Apollo 16 soils. The similarities and differences observed are discussed. The bulk compositions of Luna 20 and Apollo 16 rocks and soils show close similarity between the two highland sites. Interelement correlations observed previously for maria are also found in highland samples. Luna 20 and Apollo 16 soils are low in alkalis. Both soils show an apparent Cd-Zn rich component similar to that observed at the mare sites and high Tl abundances relative to mare sites.

Laul, J. C.↗

DOE OSTI2020

Materials Data on Zn3Cd by Materials Project

CdZn3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cd is bonded to twelve Zn atoms to form CdZn12 cuboctahedra that share corners with four equivalent CdZn12 cuboctahedra, corners with eight equivalent ZnZn8Cd4 cuboctahedra, edges with eight equivalent CdZn12 cuboctahedra, edges with sixteen equivalent ZnZn8Cd4 cuboctahedra, faces with four equivalent CdZn12 cuboctahedra, and faces with fourteen ZnZn8Cd4 cuboctahedra. There are four shorter (2.88 Å) and eight longer (2.91 Å) Cd–Zn bond lengths. There are two inequivalent Zn sites. In the first Zn site, Zn is bonded to four equivalent Cd and eight Zn atoms to form ZnZn8Cd4 cuboctahedra that share corners with twelve equivalent ZnZn8Cd4 cuboctahedra, edges with eight equivalent CdZn12 cuboctahedra, edges with sixteen ZnZn8Cd4 cuboctahedra, faces with four equivalent CdZn12 cuboctahedra, and faces with fourteen ZnZn8Cd4 cuboctahedra. There are four shorter (2.88 Å) and four longer (2.91 Å) Zn–Zn bond lengths. In the second Zn site, Zn is bonded to four equivalent Cd and eight equivalent Zn atoms to form ZnZn8Cd4 cuboctahedra that share corners with four equivalent ZnZn8Cd4 cuboctahedra, corners with eight equivalent CdZn12 cuboctahedra, edges with twenty-four ZnZn8Cd4 cuboctahedra, faces with six equivalent CdZn12 cuboctahedra, and faces with twelve ZnZn8Cd4 cuboctahedra.

36 MATERIALS SCIENCE↗