Theoretical analysis of structural stability of TM5Si3 transition metal silicides
Abstract
A combination of electronic-structure calculations from density-functional theory (DFT) through a tight-binding (TB) model to analytic bond-order potentials (BOPs) has been used to investigate the structural trend of the TM5Si3 compounds across the early transition metals (TM). First of all, the formation energies of TM5Si3 , whose ground states adopt the competing D88 , D8l , or D8m structure types, have been calculated by using DFT (TM is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, or W). In agreement with experiments the DFT results predict the observed D88→D8m structural trend across the 3d series and the D88→D8l→D8m trend across the 4d and 5d series. A p-d canonical TB model is then shown to reproduce these trends, thereby providing a valid basis for the application of BOP theory. By performing a moment analysis within the BOP formalism, we conclude that up to the fifth moment of the density of states is required to explain the structural trend across the 3d series whereas up to the ninth moment is required for the 4d and 5d series.
- Publication:
-
Physical Review B
- Pub Date:
- November 2010
- DOI:
- Bibcode:
- 2010PhRvB..82r4104C
- Keywords:
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- 71.15.Nc;
- 71.20.Lp;
- Total energy and cohesive energy calculations;
- Intermetallic compounds