TITLE:
Density Functional Study of Mechanical, Electronic and Pressure Induced Phase Transition Properties of CaFé2As2
AUTHORS:
Mochama Victor Samuel, Calford Odhiambo Otieno, Phillip Nyawere
KEYWORDS:
Phase Transition, Elastic Constants, Modulus
JOURNAL NAME:
Open Journal of Microphysics,
Vol.13 No.3,
August
7,
2023
ABSTRACT: We report results on the ab initio study of the mechanical and electronic properties of the iron Pnictide compound CaFe2As2 and its phase transition under pressure using Quantum Espresso code. We do analysis of the strength of bonds in individual points of this material and proper Cauchy pressure calculation which will give more insight on the elastic responses. Ground state energy was done in the framework of density functional theory (DFT) based on plane wave self-consistent field (PWscf) and ultrasoft pseudo potential (USPP) method as treated in the Perdew-Burke Ernzerhof (PBE) generalized gradient approximation and local density approximations. Elastic constants were computed using thermo_pw and the values were used to calculate mechanical properties and pressure phase changes. From the non-zero positive elastic constants, the Iron Pnictide compound is found to be mechanically stable and its Poisson’s ratio indicates that it is brittle and isotropic. Pressure induced phase transition is here found to happen at an applied external pressure of 0.2 GPa causing the tetragonal phase to change to an orthorhombic phase which agrees well with previous reports.