Structural, electronic, mechanical and thermodynamic properties of Cr–Si binary silicides from first-principles investigations

Abstract

Abstract Cr–Si binary silicides are promising advanced functional materials, which are widely used in semiconductors, thermoelectric and high temperature industries. However, the correlation between structural feature and the overall properties of Cr–Si silicides are not unclear. Here, we apply the first-principles to study the structural, mechanical, electronic and thermodynamic properties of Cr–Si silicides. The result shows that one novel Cr2Si orthorhombic structure (Pnma) is predicted. It is found that the calculated bulk modulus of Cr–Si silicides decreases with increasing Si concentration. The calculated shear modulus and Young's modulus of Cr3Si are larger than that of the other Cr–Si silicides because of the symmetrical Cr–Si bonds. However, Cr2Si shows better ductility and good plasticity in comparison to the other Cr–Si silicides. Compared to the CrSi2, these Cr–Si silicides show better electronic properties. Finally, it is found that the calculated Debye temperature (ΘD) of Cr–Si silicides obeys the sequence of Cr5Si3>CrSi > Cr3Si > Cr2Si. Naturally, the high-temperature thermodynamic properties of Cr–Si silicides are attributed to the vibration of Si atom and Cr–Si bond. This work provides a theoretical framework for understanding the comprehensive properties of Cr–Si silicides and provides powerful guidelines for future improving the overall performances of Cr–Si silicides.