Abstract
The structural stability and the electronic structure of were studied using an all-electron, total-energy, local-density approach. The calculated results show that in the L structure is energetically favored compared with the D structure by about 0.42 eV per formula unit. The calculated lattice constant (4.055 Å) is in fairly good agreement with experiment (4.10 Å). As a comparison, the calculated electronic and cohesive properties for in its metastable L and D phases are also presented. It is argued, on the basis of density-of-states results, that a cubic compound (and also ) might be a good candidate as a dispersed phase in the aluminum alloys for elevated temperature applications. To test this prediction, we determined the electronic structure and the stability of Sc-stabilized cubic () using the same total-energy approach. The calculated total energy for (), which is about 0.24 eV per unit cell lower than the sum of the total energies of and , clearly indicates that cubic () is energetically favored compared with a mixture of its constituents. Finally, an analysis of the results indicates that the stability of the aluminides appears to be understood in the rigid-band sense in terms of the band filling of the bonding states.
- Received 12 March 1990
DOI:https://doi.org/10.1103/PhysRevB.41.12553
©1990 American Physical Society