Effect of exchange-correlations and pseudopotentials on the structural and cohesive properties of fundamental refractory metals (Nb, Mo, Ta, W and Re)

The effect of exchange–correlation (XC) and pseudopotentials in the density functional theory (DFT)-based calculations of lattice constants and cohesive energies for five fundamental refractory metals niobium (Nb), molybdenum (Mo), tantalum (Ta), tungsten (W) and rhenium (Re) has been studied. The LDA and PBEsol XCs show an over prediction of cohesive energies by 12–23% and 2–12% respectively, when compared to the experimental results. PBE XCs produce little underestimated (2–9%) cohesive energies for Nb, Mo, W and Re with only the exception of Ta; where it overpredicts the experimental value by 2%. Whereas for the equilibrium lattice parameter, our computed values are in good agreement with the reported values, an over or under-binding of only 1–2% has been observed. Graphical abstract Effect of different correlation functionals on cohesive energy of refractory metals