Two sets of maximally localized Wannier functions (MLWFs)
[25] were constructed to investigate the mechanism of the metal–
insulator transition using the Wannier90 package and its interface
to VASP [26]. The first set of MLWFs is d band only, each function is
of hybridized transitional metal 3d orbital and the neighboring O
2p feature. The other set of WLWFs, which is constructed to calculate
the layer resolved polarization, consists of all the occupiedorbital-like
wave functions.