2002/09/30 by T. R. Kirkpatrick, D. Belitz · 2 citations
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Theoretical and Computational Physics #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.67.024419
published as Phys. Rev. B 67, 024419 (2003) · 15 pp., revtex4, 6 eps figs; final version as published
openalex publication_date 2003/01/22 · arxiv created 2003/07/17 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A comprehensive theory of the quantum phase transition in clean itinerant Heisenberg ferromagnets is presented. It is shown that the standard mean-field description of the transition is invalid in spatial dimensions d<~3 due to the existence of soft particle-hole excitations that couple to the order parameter fluctuations and lead to an upper critical dimension dc+=3. A generalized mean-field theory that takes these additional modes into account predicts a fluctuation-induced first-order transition. In a certain parameter regime, this first-order transition in turn is unstable with respect to a fluctuation-induced second-order transition. The quantum ferromagnetic transition may thus be either of first or of second order, in agreement with experimental observations. A detailed discussion is given of the stability of the first-order transition and of the critical behavior at the fluctuation-induced second-order transition. In d=3, the latter is mean field like with logarithmic corrections to scaling, and in d<3 it can be controlled by means of a 3\ensuremath-\ensuremathε expansion.