2005/06/30 by Serge Florens, Matthias Vojta · 1 citation
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Rare-earth and actinide compounds #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.72.115117
published as Phys. Rev. B 72, 115117 (2005) · 10 pages, 8 figures. Minor modifications in updated version
arxiv created 2005/08/08 · openalex publication_date 2005/09/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Numerical renormalization group simulations have shown that the underscreened spin-1 Kondo impurity model with power-law bath density of states (DOS) \ensuremathρ(\ensuremathω)\ensuremath∝\ensuremath|\ensuremathω\ensuremath|r possesses various intermediate-coupling fixed points, including a stable non-Fermi-liquid phase. In this paper we discuss the corresponding universal low-energy theories, obtain thermodynamic quantities and critical exponents by renormalization group analysis together with suitable ϵ expansions, and compare our results with numerical data. Whereas the particle-hole symmetric critical point can be controlled at weak coupling using a simple generalization of the spin-1∕2 model, we show that the stable non-Fermi-liquid fixed point must be accessed near strong coupling via a mapping onto an effective ferromagnetic Seff=1∕2 model with singular bath DOS with exponent reff=\ensuremath-r<0. In addition, we consider the particle-hole asymmetric critical fixed point, for which we propose a universal field theory involving the crossing between doublet and triplet levels.