Spin fluctuations and ferromagnetic order in two-dimensional itinerant systems with Van Hove singularities

Abstract

The quasistatic approach is used to analyze the criterion of ferromagnetism for two-dimensional (2D) systems with the Fermi level near Van Hove (VH) singularities of the electron spectrum. It is shown that the spectrum of spin excitations (paramagnons) is positively defined when the interaction between electrons and paramagnons, determined by the Hubbard on-site repulsion U, is sufficiently large. Due to incommensurate spin fluctuations near the ferromagnetic quantum phase transition, the critical interaction Uc remains finite at VH filling and exceeds considerably its value obtained from the Stoner criterion. A comparison with the functional renormalization group results and mean-field approximation which yields a phase separation is also performed.

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Cited by in corpus (6)

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• Magnetic fluctuations and self--energy effects in two--dimensional itinerant systems with van Hove singularity of electronic spectrum
• Electronic correlations, spectral and magnetic properties of ZrZn${}_2$
• The quantum critical behavior of antiferromagnetic itinerant systems with van Hove singularities of electronic spectrum
• Ferromagnetic instability in itinerant fcc lattice electron systems with higher order van Hove singularities: Functional renormalization group study
• Ferromagnetism, spiral magnetic structures and phase separation in the two-dimensional Hubbard model