Electronic, mechanical, phase transition and thermo-physical properties of TiC, ZrC and HfC: High pressure computational study

• In the present work, two different ab-initio methods, viz., pseudo- and full-potential based are used.
• Structural phase transformation from B1 to B2 phase has been studied.
• Electronic behavior for these materials have been analyzed in B1 and B2 phases simultaneously for the first time.
• Mechanical and thermo-physical properties are also investigated in both phases.

Structural, electronic, mechanical and thermo-physical properties of refractory carbides (TiC, ZrC and HfC) have been investigated in the stable B1 as well as high pressure B2 phase along with the high pressure phase transition in these materials by two different pseudo- and full-potential approaches. The results are compared with experiments to adjudge the effectiveness of both approaches. Band structure and DOS calculations provide evidence for metallic (finite DOS at EF) and covalent (C (p)–TM (d) hybridization) bonding in these materials in both phases. Ionic bonding is also revealed from charge density plots. Covalent nature dominates in B1 phase while ionic bonding in B2 phase. The elastic constants show the mechanical stability of these carbides in B1 phase and instability in B2 phase. These materials are brittle and anisotropic in B1 phase. Elastic wave velocities and the Debye temperatures have also been reported. The present results show good agreement with the measured data. However, some of the calculations are reported for the first-time.

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