High pressure phase transition and elastic properties of ytterbium compounds YbX (X=O, S, Se and Te)

We have investigated structural stability, high pressure structural behaviour, elastic and thermo-physical properties of ytterbium compounds YbX (X=O, S, Se, Te) using an improved interaction potential model (IIPM). This model incorporates long range coulomb interaction, three body interaction, polarizability effect and short range overlap repulsive interactions extended up to second nearest neighbours. The ytterbium compounds show iso-structural phase transition under pressure. YbX are predicted to exhibit a phase transition from NaCl to CsCI-type structure at high pressure. To our knowledge this is the first theoretical prediction of structural, elastic and thermo physical properties of these compounds and still awaits experimental confirmations. Due to unavailability of experimental and theoretical data on these compounds we have compared our results with other compounds MX (M=Eu, Ce) which belong to group of same structure (B1) and show same transition (B1-B2) under pressure.