Study of effect of covalency in heavy rare-earth monoantimonides upto 31 GPa

In the present paper, we have investigated the high-pressure structural phase transition of rare earth antimonides (HoSb and TmSb). A modified interaction potential model (MIPM) (including the covalency effect) has been developed. Phase transition pressures are associated with a sudden collapse in volume. At compressed volumes, these compounds are found in CsCl phase. The phase transition pressures and associated volume collapses obtained from present potential model show a generally good agreement with available experimental data and others. The elastic constants and bulk modulus are also reported. Our results are in general in good agreement with experimental and theoretical data where available, and provide predictions where they are unavailable.

Graphical abstractPhase transition pressures are associated with a sudden collapse in volume. At compressed volumes, these compounds go from NaCl to CsCl phase.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► In the present paper, we have investigated the high-pressure structural phase transition of rare earth antimonides (HoSb and TmSb). ► A modified interaction potential model (MIPM) (including the covalency effect) has been developed. ► Phase transition pressures are associated with a sudden collapse in volume. At compressed volumes, these compounds are found in CsCl phase. ► Due to the inclusion of charge transfer effect our model is able to explain Cauchy violations (C12 ≠ C44). ► The present results of phase transition pressures and volume collapses show a generally good agreement with available experimental data and others.