Electronic structure of the β-modification LiNH₄SO₄ crystal with a Cu²⁺ impurity

The work investigates the band-energy structure of the LiNH4SO4 crystal in -modification with Cu 2+ impurity.For this purpose, electronic structure modeling within the framework of density functional theory was used.Before calculations, geometric optimization of the crystal structure was carried out using the BFGS method.The features of the crystal structure of the LiNH4SO4 crystal in -modification with Cu 2+ impurity were clarified.It is shown that the addition of a copper impurity leads to the appearance of additional d-electron levels in the band gap of the crystal.These levels are located at an energy of 1.96 eV above the top of the valence band of the pure crystal.The location of the copper levels is close to that previously obtained for the K2SO4:Cu 2+ crystal.It is shown that the levels of the copper d-states are higher than the levels for manganese atoms in the studied crystal.