Non-Fermi-liquid behavior and anomalous suppression of Landau damping in layered metals close to ferromagnetism

Abstract

We analyse the low-energy physics of nearly ferromagnetic metals in two spatial dimensions using the functional renormalization group technique. We find a new low-energy fixed point, at which the fermionic (electron-like) excitations are non-Fermi-liquid ($z_f = 13/10$) and the magnetic fluctuations exhibit an anomalous Landau damping whose rate vanishes as $\Gamma_{\bf q} \sim \vert {\bf q} \vert^{3/5}$ in the low-$\vert {\bf q} \vert$ limit. We discuss this renormalization of the Landau-damping exponent, which is the major novel prediction of our work, and highlight the possible link between that renormalization and neutron-scattering data on UGe$_2$ and related compounds. Implications of our analysis for YFe$_2$Al$_{10}$ are also discussed.Comment: 5 pages, 3 figures; action modified to include spin of fermions, resulting in quantitative changes to exponents but same essential physic