2002/12/31 by V. Yu. Irkhin, A. V. Zarubin, А. В. Зарубин · 23 citations
Materials Science · Physics and Astronomy · Psychology · #Computer science #Condensed matter physics #Ferromagnetism #Hubbard model #Machine learning #Magnetic and transport properties of perovskites and related materials #Physics #Physics of Superconductivity and Magnetism #Psychology #Quantum and electron transport phenomena #Stability (learning theory) #Statistical physics #Superconductivity #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.70.035116
published in Physical Review B 70(3) (American Physical Society) · 16 pages, 7 eps figures
arxiv created 2004/01/23 · openalex publication_date 2004/07/29 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The problem of stability of saturated and nonsaturated ferromagnetism in the Hubbard model is considered in terms of the one-particle Green's functions. Approximations by Edwards and Hertz and some versions of the self-consistent approximations based on the 1∕z expansion are considered. The account of longitudinal fluctuations turns out to be essential for description of the nonsaturated state. The corresponding pictures of density of states are obtained. ``Kondo'' density-of-states singularities owing to spin-flip processes are analyzed. The critical electron concentrations for instabilities of saturated ferromagnetism and paramagnetic state are calculated for various lattices. Drawbacks of various approximations are discussed. A comparison with the results of previous works is performed.