Phase stability of BCC transition metals: Role of d-electrons

The role of d-electrons in the structural phase stability of bcc transition metals viz. V, Fe, Cr and Mn are investigated. The underlying theory expresses the relevant structural part of the free energy in terms of the repulsion of the d-electron muffin-tin orbitals assigned to atomic sites and the attractive contribution arising from the band broadening effects of the d-bands in the total energy. The magnetic contribution arising from the population of magnetic moments in the systems is also included in the theory. The delectronic contribution to entropy is written in terms of the density-of-electronic states at the respective Fermi level. The phase stability of the bcc transition metals is explained in terms of the population of atoms on the local and extended sites. It is observed that the d-electron energetics can precisely and correctly predict the crystal structure of the bcc transition metals.