Pressure-induced physical properties in topological semi-metals MAs2M=Hf,Ti

• Published in: Results in physics 2023-09, Vol.52, p.106860, Article 106860
• Main Authors: Khan, Mithun, Rakib Hossain, Md, Lokman Ali, Md
• Format: Article
• Language: English
• Subjects: Elastic properties; Electronic properties; First principle calculations; Mechanical properties; Optical properties; Topological semi metal
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2023.106860

•Effects of pressure on the physical properties of MAs2 (M = Hf, Ti) topological semi metals were studied.•The compounds turned brittle to ductile nature after applying pressure above 20 GPa.•All the mechanical properties demonstrated the prominent effects of applied pressure.•The applied pressure tuned the band structure of MAs2 (M = Hf, Ti) semi metals significantly.•The compounds can be used as a potential coating materials in some specific purpose. The present study employs first-principles DFT-based calculations within the generalized gradient approximation (GGA) to reveal various physical feature (including structural, elastic, mechanical, electronic, optical, as well as Debye temperature) of the topological semimetal MAs2M=Hf,Ti under stress up to 50GPa. Mechanical and thermodynamic stability of the investigated materials are supported by Born stability criteria and formation energy. To learn more about the mechanical features of MAs2M=Hf,Ti materials, we investigated at a variety of metrics such elastic constants, elastic moduli, Vickers hardness, machinability index, Kleinman parameter, and anisotropy factor. Interestingly, both Pugh’s ratio and Poisson’s ratio reveal that studied materials go through a brittle-to-ductile transition at different applied pressures. Due to the increase in elastic constants with increasing pressure, materials become more rigid and resistant to deformation, making them useful in various engineering fields. The studied materials are anisotropic, and their anisotropy factor changes significantly with rising pressure. The band structure analysis confirms that both materials are Weyl semi-metals, and the density of states reveals that the d orbital of Hf and Ti contributes significantly to DOS at EF. The electrical characteristics are strongly supported by the optical function. As external pressure increases, there is a corresponding increase in both the absorption coefficient and reflectivity. Their refractive index value falls and becomes flat at high energy, making them a high-density optical data storage media when exposed to the right light source. For both the material, pressure increases density, sound velocity, and Debye temperature, indicating that covalent bonds become stronger. The higher value of Debye temperature indicates the higher melting point of the studied compounds.