Phase transition, structural, mechanical and thermal properties of erbium pnictides under pressure

Abstract

In this article, we have investigated the high-pressure structural phase transition of erbium pnictides (ErX; X = N, P and As). An extended interaction potential model has been developed (including the zero-point energy effect in three-body interaction potential model). Phase transition pressures are associated with a sudden collapse in volume. The phase transition pressures and associated volume collapses have been predicted successfully. The elastic constants, their combinations and pressure derivatives are also reported. The pressure behaviour of elastic constants, bulk modulus and shear modulus have been presented and discussed. Moreover, the thermophysical properties such as molecular force constant (f), infrared absorption frequency (υ ₀), Debye temperature (θ _D) and Grunneisen parameter (γ) have also been predicted.

Keywords:

• high pressure
• elastic properties
• phase transitions
• crystal structure

Acknowledgements

One of the authors (Purvee Bhardwaj) is grateful to the Department of Science and Technology, New Delhi, for awarding WOS-‘A’ and the financial support to this study.