Ab Initio Studies on Structural, Elastic, Thermodynamic and Electronic Properties of FeCrAs under Pressures

De-Chun Hea, Yong Peng a and Yong-Wei He b aPhysical and Mechanical and Electrical Engineering College, Hexi University, Zhangye Gansu, 734000, China bInstitute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China

Received: August 11, 2014; In final form: February 10, 2015

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The structural, elastic, thermodynamic and electronic properties of nonmetallic metal FeCrAs are studied within density function perturbation theory. The thermodynamic properties of FeCrAs were deduced based on phonon frequencies within the framework of the quasiharmonic approximation. The calculated elastic modulus under various pressures indicates that FeCrAs is mechanically stable under pressure. The pressure-dependence of bulk and shear modulus, transverse and longitudinal sound velocities V (i.e. VS and VL), elastic Debye temperature ΘE of FeCrAs have also been investigated. The calculated values of B/G indicate that FeCrAs presents high ductility under pressure. However, it is interesting that the value of B/G reaches a maximum under 40 GPa and almost remains unchanged when the pressure is above 70 GPa. The calculations show that the heat capacity CV of this material is close to the Dulong-Petit limit 3R (about 224.61 J mol-1 K-1) at high temperature regime. The analysis of electronic properties find that as the pressure increases, the absolute value of charge for As and Fe atom increases while Cr remains nearly a constant, indicating that the mechanic properties of FeCrAs under pressure should be mostly attributed to the interaction between Fe and As atoms.

DOI: 10.12693/APhysPolA.127.1637 PACS numbers: 62.20.de, 65.40.Ba, 65.40.De, 72.15.-v