Anomalous self-energy and Fermi surface quasisplitting in the vicinity of a ferromagnetic instability

A. A. Katanin, A. P. Kampf, V. Yu Irkhin

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18 Citations (Scopus)

Abstract

We discuss the low-temperature behavior of the electronic self-energy in the vicinity of a ferromagnetic instability in two dimensions within the two-particle self-consistent approximation, functional renormalization group, and Ward-identity approaches. Although the long-range magnetic, order is absent at T > 0. the self-energy has a non-Fermi-liquid form at low energies |ω| ≲ Δ 0 near the Fermi level, where Δ 0 is the ground-state spin splitting. The spectral function at temperatures T ≲ Δ 0 has a two-peak structure with finite spectral weight at the Fermi level. The simultaneous inclusion of self-energy and vertex corrections shows that the above results remain qualitatively unchanged down to very low temperatures T ≪ Δ 0. It is argued that this form of the spectral functions implies the quasisplitting of the Fermi surface in the paramagnetic phase in the presence of strong ferromagnetic fluctuations.

Original languageEnglish
Article number085105
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume71
Issue number8
DOIs
Publication statusPublished - Feb 2005
Externally publishedYes

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