Spectral functions of 2D systems with coupling of electrons to collective or localized spin degrees of freedom

Abstract

The spectral properties of itinerant 2D systems with (nearly) ferromagnetic ground state are studied within the spin-fermion and the classical s-d exchange models. While the former model describes the effect of collective magnetic excitations on the electronic properties, the latter one considers the effect of local moments. We use the equation of motion approach combined with the 1/M and 1/z expansions (M is the number of spin components, z is the coordination number) to investigate spectral functions. In both the models the spectrum splitting occurs at low temperatures T in the renormalized classical regime due to strong magnetic fluctuations. For the interaction J between electronic and magnetic degrees of freedom comparable to the bandwidth (the intermediate-coupling regime) the 1/z expansion predicts full splitting of electronic spectrum below some temperature T_s. At the same time, the spectrum remains only partly split in the 1/M expansion with the quasiparticle structure which becomes fully coherent at low T.

13 pages, 10 figures, RevTex

References in corpus (4)

• Dynamical vertex approximation - a step beyond dynamical mean field theory
• Influence of Spatial Correlations in Strongly Correlated Electron Systems: Extension to Dynamical Mean Field Approximation
• Antiferromagnetism and single-particle properties in the two-dimensional half-filled Hubbard model: a non-linear sigma model approach
• Electronic self-energy and triplet pairing fluctuations in the vicinity of a ferromagnetic instability in 2D systems: the quasistatic approach

Cited by in corpus (7)

• Modern Physics of the Condensed State: Strong Correlations and Quantum Topology
• Fermi surface expansion above critical temperature in a Hund ferromagnet
• Spin fluctuations and ferromagnetic order in two-dimensional itinerant systems with Van Hove singularities
• Magnetic properties of half metal from the paramagnetic phase: DFT+DMFT study of exchange interactions in CrO${}_2$
• A Contemporary Model Description of Magnetism
• A Modern Model Description of Magnetism
• Diagrammatic bosonization, aspects of criticality, and the Hohenberg-Mermin-Wagner theorem in parquet approaches