The lattice vibration, mechanical anisotropy, stress-strain behavior and electronic properties of HfxSiy phases: A first-principles study

The lattice vibrations, elastic anisotropy, electronic properties and stress-strain behavior of HfxSiy phases were predicted using a first-principles calculations. The enthalpies of formation and lattice vibration frequencies of HfxSiy confirmed that they are phase-stable. The results of the elastic hardness show that they are elastically anisotropic. The order of anisotropy is Hf3Si2 > HfSi > Hf2Si > HfSi2 > Hf5Si3 > Hf5Si4. HfSi2 has a maximum hardness value of 19.7 GPa and is less than 20 GPa, indicating that it is not a potential superhard material. The results of stress-strain stretching increase with stretching and start a decreasing trend after the stress value reaches its highest point. Finally, we predicted sound velocity and Debye temperature.