Electronic, thermodynamic and mechanical properties of CrAs

In spintronics, transition-metal pnictides, such as CrAs in the metastable zinc-blende lattice structure, have attracted much interest due to their half-metallic ferromagnetism properties. In this paper, we have investigated the properties of CrAs in NiAs and zinc-blende structures by using ESPRESSO code. The calculations are based on the Density Functional Theory (DFT) and the Density Functional Perturbation Theory (DFPT) with the generalized gradient approximation (GGA).The Results show that CrAs in NiAs phase is metal and in zinc-blende phase is half-metal with direct band gap. The value of gap energy is 1.94 eV which is in good agreement with other previous calculations ( 1.88, 1.85, 1.87 and 1.8 eV). We have calculated Bulk module by fitting the lattice constants data to the Murnaghan equation of state. The elastic constants are calculated by using the slop of the phonon acoustic modes. The constants in NiAs phase are C11= 139.1 ,C66=83.4 ,C44=38.9 , C33=90.1 ,C12=61.1 , C13=85.4 and in zinc-blend phase are C11= 82.9 ,C44=24.5 , C12=60.1 and . According to our investigation, the elastic constants have not been calculated so far.