2008/07/29 by Grzegorz Górski, Grzegorz Gorski, Jerzy Mizia
Materials Science · Physics and Astronomy · #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.79.064414
29 pages, 5 figures
arxiv created 2008/07/29 · openalex publication_date 2009/02/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We presented the intersite electron-electron correlation into the Hubbard III approximation. This correlation was excluded in the Hubbard III approximation and also in the equivalent coherent-potential approximation. Including it brings two spin-dependent effects: the bandwidth correction and the band shift correction, which both stimulate the ferromagnetic ground state. The band shift correction factor causes an exchange splitting between the spin-up and spin-down spectra, and its role is similar to the exchange interaction in the classic Stoner model. The spin-dependent bandwidth correction lowers the kinetic energy of electrons by decreasing the majority-spin bandwidth for some electron occupations with respect to the minority-spin bandwidth. In certain conditions it can lead to ferromagnetic alignment. A gain in the kinetic energy achieved in this way is the opposite extreme to the effect of a gain in potential energy due to exchange splitting. The band shift factor is a dominant force behind the ferromagnetism, but the presence of both factors working together is necessary to create spontaneous magnetization.