Spin fluctuations and ferromagnetic order in two-dimensional itinerant systems with Van Hove singularities - Condensed Matter > Strongly Correlated ElectronsReport as inadecuate




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Abstract: The quasistatic approach is used to analyze the criterion of ferromagnetismfor two-dimensional 2D systems with the Fermi level near Van Hove VHsingularities of the electron spectrum. It is shown that the spectrum of spinexcitations paramagnons is positively defined when the interaction betweenelectrons and paramagnons, determined by the Hubbard on-site repulsion U, issufficiently large. Due to incommensurate spin fluctuations near theferromagnetic quantum phase transition, the critical interaction Uc remainsfinite at VH filling and exceeds considerably its value obtained from theStoner criterion. A comparison with the functional renormalization groupresults and mean-field approximation which yields a phase separation is alsoperformed.



Author: P. A. Igoshev, A. A. Katanin, H. Yamase, V. Yu. Irkhin

Source: https://arxiv.org/







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