Pressure-induced electronic, magnetic, half-metallic, and mechanical properties of half-Heusler compound CoCrBi

The structural, electronic, magnetic, half-metallic and mechanical properties of half-Heusler alloy CoCrBi under pressure have been studied by first-principle calculations. CoCrBi is found to be half-metallic under the uniform pressure from 7.45 to 295 GPa, and the total magnetic moment is 2.00 mu(B) per formula unit. The transitions from metal to half-metal and from half-metal to metal occur at 7.45 and 295 GPa, respectively. The calculations show that the uniform pressure has an important influence on the minority-spin states, leading to a slight reconstruction of the minority-spin states with a shift of Fermi level. The calculated elastic constants revel that the mechanical instability will occur if the pressure is greater than 47.6 GPa. Two kinds of tetragonal distortions under non-uniform pressure are also studied. It is found that the change of c/a ratio has no obvious influence on the electronic structures and magnetic properties, whereas, compressing the lattice constant in one direction can also realize the transition from metallic to half-metallic properties for CoCrBi. (C) 2017 Elsevier B.V. All rights reserved.