Since the exact mechanism of superconductivity has not been completely understood yet, investigating this phenomenon is of great interest. Here, we first studied CuO₂ and La₂O₂ monolayers separately and then investigated the changes in the electronic structure of the layered La₂CuO₄ as formed by stacking those monolayers together. The results showed that when the two layers are sandwiched in tandem, a charge transfer mechanism occurs initially from La₂O₂ to CuO₂. This charge transfer mechanism results in localized orbitals that contribute to the bonds in CuO₂, making them stronger. On the other hand, Cu dz2 orbitals move toward the Fermi level, being more delocalized. This phenomenon occurs by changing the crystal field effect on Cu atoms and creating the octahedral coordination of O atoms around Cu atoms. Therefore, due to the crystal field effect, the energy level of dz2 orbitals, which lie under those of dxz + dyz and dxy orbitals, ascend and lie under the energy level of dx2y2 orbitals. These changes in the electronic structure create a half-filled band around the Fermi level consisted of Cu dx2y2 and dz2 orbitals and apical O Pz orbitals. This configuration occurs by emptying the states due to La₂O₂ near the Fermi level and occupying the states due to CuO₂, lowering the bands in energy. The lowering separates the band around the Fermi level from other bands.