Electronic basis of the hcp, omega and bcc phases in group IVB elements under pressure or on alloying

Using the first principles DFT calculations, we have elucidated the electronic basis of the α→ω and the ω→β transitions in group IVB elements. After considering several possible factors that could give rise to the structural stability of a particular crystal structure, the changes in the band structure energy due to Peierls–Jahn–Teller distortion and crystal-field effects on sub orbital of d bands coupled with Ewald energy differences have been identified as the causes for these transitions. The role of van Hove singularities and consequent electronic topological transitions has also been examined.

► Electronic basis of phase transitions in Group IV B elements has been given.
► This is related to pseudo-gaps in the respective density of states.
► Density functional theory is employed.
► Symmetry breaking, crystal fields and van Hove singularities are factors cosidered.
► Direct α→β phase change in the latest group IVB element Rf is rationalized.