Hey Yp Hu

Typically, DFT+U is commonly applied to elements with highly localized electrons, say transition metals or rare earths. Why are you considering using this approach on W and Nb if they do not have strongly localized d or f electrons?

Best,

Gabriel Vinicius

For a specific material, you can

• either determine the U value empirically by comparing the material properties of interest to relevant values (like e.g. in [Phys. Rev. B 82 (2010) 184430])
• or calculate the U value from first principles as described in [Phys. Rev. B 98 (2018) 085127] and implemented in some DFT codes.

Best regards.