M. Roknuzzaman

Zirconium metal-based MAX phases Zr2AC (A = Al, Si, P and S): A first-principles study

We have investigated theoretical Vickers hardness, thermodynamic and optical properties of four zirconium metal-based MAX phases Zr 2 AC (A = Al , Si , P and S ) for the first time in addition to revisiting the structural, elastic and electronic properties. First-principles calculations are employed based on density functional theory (DFT) by means of the plane-wave pseudopotential method. The theoretical Vickers hardness has been estimated via the calculation of Mulliken bond populations and electronic density of states. The thermodynamic properties such as the temperature and pressure dependent bulk modulus, Debye temperature, specific heats and volume thermal expansion coefficient of all the compounds are derived from the quasi-harmonic Debye model. Further, the optical properties, e.g., dielectric functions, indices of refraction, absorption, energy loss function, reflectivity and optical conductivity of the nanolaminates have been calculated. The results are compared with available experiments and their various implications are discussed in detail. We have also shed light on the effect of different properties of Zr 2 AC as the A-group atom moves from Al to S across the periodic table.

Structural, elastic, and electronic properties of recently discovered ternary silicide superconductor Li2IrSi3: An ab-initio study

The structural, elastic, and electronic properties of the very recently discovered ternary silicide superconductor, Li2IrSi3, have been calculated using ab-initio technique. We have carried out the plane-wave pseudopotential approach within the framework of the first-principles density functional theory (DFT) implemented within the CASTEP code. The calculated structural parameters show a reasonable agreement with the experimental results. Elastic moduli of this interesting material have been calculated for the first time. The electronic band structure and electronic energy density of states indicate the strong covalent Ir-Si and Si-Si bonding which lead to the formation of the rigid structure of Li2IrSi3. Strong covalency give rise to a high Debye temperature in this system. We have discussed the theoretical results in detail in this paper.

Structural, Elastic, and Electronic Properties of Newly Discovered Li2PtSi3 Superconductor: Effect of Transition Metals

A density functional study with a GGA-PBE exchange-correlation scheme has been carried out to predict the structural, elastic, and electronic properties of the newly discovered lithium silicide superconductor, Li2PtSi3, for the first time. All the theoretical results are compared with those found recently for isostructural Li2IrSi3. This study sheds light on the important effect of replacement of the transition metal element Ir with Pt, on different mechanical, electronic, and superconducting properties. The role of spin–orbit coupling on the electronic band structure is found to be insignificant for Li2PtSi3. The difference in superconducting transition temperatures of Li2PtSi3 and Li2IrSi3 arises primarily due to the difference in electronic energy density of states at the Fermi level. Somewhat reduced Debye temperature in Li2PtSi3 plays a minor role. We have discussed the implications of the theoretical findings in details in this paper.