Structural, electronic, mechanical and superconducting properties of ReC and TcC

• Ground state properties of ReC and TcC are investigated.
• A sequence of structural phase transition is predicted under high pressure.
• Electronic structure reveals that these materials exhibit metallic behavior.
• These materials are found to be superhard materials.
• The superconducting transition temperature values are computed for ReC and TcC.

The structural, electronic, mechanical and superconducting properties of rhenium carbide (ReC) and technetium carbide (TcC) are investigated using first principles calculations based on density functional theory (DFT). The computed ground state properties like equilibrium lattice constants and cell volume are in good agreement with the available experimental and theoretical data. It is observed that tungsten carbide phase (WC) is the most stable phase for ReC and TcC at normal pressure. Pressure induced structural phase transitions are observed from tungsten carbide to zinc blende phase and then zinc blende to wurtzite phase in rhenium carbide while tungsten carbide to zinc blende phase and then zinc blende to nickel arsenide phase in technetium carbide. Electronic structure reveals that these materials are metallic at ambient condition. The high bulk modulus (B) value of WC phase of both ReC (438 GPa) and TcC (368 GPa) suggests that they are ultra hard and incompressible materials. Also, the superconducting transition temperature is estimated for ReC and TcC at normal pressure.

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