The pressure induced B1–B2 phase transition of alkaline halides and alkaline earth chalcogenides. A first principles investigation

In this work, we considered the pressure induced B1–B2 phase transition of AB compounds. The DFT calculations were carried out for 11 alkaline halides, 11 alkaline earth chalcogenides and the lanthanide pnictide CeP. For both the B1 and the B2 structures of each compound, the energy was calculated as a function of the cell volume. The transition pressure, the bulk moduli and their pressure derivatives were obtained from the corresponding equations of state. The transition path of the Buerger mechanism was described using roots of the transition matrix. We correlated the computed enthalpies of activation to some structure defining properties of the compounds. A fair correlation to Pearsons hardness of the ions was observed.

Pressure induced transition from the B1 structure (left) via the transition state (middle) to the B2 structure (right).Figure optionsDownload as PowerPoint slideHighlights
► Pressure induced phase transitions in AB compounds were considered.
► Alkaline halides and alkaline earth chalcogenides were treated.
► DFT calculations with periodic boundary conditions were applied.
► The transition path was described by roots of the transition matrix.
► The enthalpy of activation was calculated for numerous compounds.