Mechanical properties and electronic structures of the Hf-Si system: First-principles calculations

Structural, elastic, mechanical and electronic properties of Hf_xSi_y compounds have been investigated using the first-principles density-functional theory (DFT) within the generalized gradient approximation (GGA) for the exchange-correlation functional. The ground-state properties such as structural parameters and formation enthalpies of Hf₂Si, Hf₅Si₃, Hf₃Si₂, Hf₅Si₄, HfSi and HfSi₂ have been obtained, indicating that the stability sequence of ^HfxSiy compounds is HfSi₂<Hf₂Si<Hf₅Si₃<Hf₃Si₂<HfSi<Hf₅Si₄ at zero temperature and zero pressure. The independent elastic constants, bulk modulus, shear modulus, Youngs modulus, Poissons ratio and bulk modulus to shear modulus ratio of ^HfxSiy compounds have been calculated. The results show that ^HfxSiy compounds are all mechanically stable. Moreover, we show the band structures and density of states of ^HfxSiy compounds.