Newly synthesized nanolaminate Nb2GeC: Hardness, thermodynamic and optical properties by first-principles method

• Mulliken bond overlap, theoretical hardness and Fermi surface of Nb2GeC.
• Finite-T, finite-P thermodynamic and optical properties of Nb2GeC.
• The Fermi surface contains hole-like sheets centered along Г–A direction.
• Promise of a good reflector in the IR–UV regions up to 16 eV.

The thermodynamic and optical properties of newly synthesized nanolaminate Nb2GeC are reported by first-principles DFT calculations. The bulk modulus, Debye temperature, and specific heats, and thermal expansion coefficient are successfully obtained through the quasi-harmonic Debye model in the temperature range from 0 to 1200 K. The calculated results have been compared with available data of similar types of MAX phases (Nb2SC and Nb2SnC). The theoretical Vickers hardness of Nb2GeC is found to be 4.15 GPa. The optical parameters (dielectric function, refractive index, real part of conductivity, absorption, loss function, and reflectivity) of Nb2GeC have been evaluated. The reflectivity is seen to be high in the IR–UV region up to ∼16 eV showing promise as a good coating material.