Bandfilling and structural stability of trialuminides: YAl sub 3 , ZrAl sub 3 , and NbAl sub 3
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208-3112 (USA) Shanghai Institute of Metallurgy, Academy of Sciences of China, Shanghai 200050, China (CN)
- Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208-3112 (USA) Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (USA)
The cohesive properties and electronic structure versus the structural stability of transition-metal trialuminides YAl{sub 3}, ZrAl{sub 3}, and NbAl{sub 3} in their cubic L1{sub 2}, tetragonal D0{sub 22}, and naturally stable forms (i.e., the D0{sub 19} structure for YAl{sub 3} and the D0{sub 23} structure for ZrAl{sub 3}) have been investigated using a total energy local-density approach. The variation of structural stability with transition-metal constituent can be simply understood in terms of the bandfilling of the bonding states in the rigid band sense, with the valence electrons gradually filling the bonding states on going from YAl{sub 3}, ZrAl{sub 3} to NbAl{sub 3}. This leads to a phase transition from the cubic L1{sub 2} structure (for YAl{sub 3}) to the tetragonal D0{sub 22} structure (for NbAl{sub 3}). It is argued that this criterion may also apply to explain the variation of the structural stability of other transition-metal compounds (such as transition-metal carbides, nitrides, silicides, etc.) that are dominated by covalent interactions between the transition-metal {ital d} and the metalloid {ital p} states.
- OSTI ID:
- 5693064
- Journal Information:
- Journal of Materials Research; (USA), Vol. 6:6; ISSN 0884-2914
- Country of Publication:
- United States
- Language:
- English
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