Pressure induced structural phase transformation in rare earth ytterbium pnictides

We have studied the pressure - volume relationship and pressure induced structural phase transformation in ytterbium pnictide compounds (YbN, YbP and YbAs) for the first time by using an interatomic potential approach based on rigid ion model, which considers only Coulomb and Born- Mayer type short range interaction. The theoretically predicted pressure - volume relationship curve shows that the YbN, YbP and YbAs exhibit normal compression and undergo the NaCl to CsCl type structural transition at 164, 115 and 95 GPa respectively, similar to the europium chalcogenides instead of their counterparts Yb-chalcogenides, where the compression curve shows the anomalous nature due to change in the valence state. (author)