2004/04/22 by Alba Theumann, B. Coqblin · 2 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Theoretical and Computational Physics #cond-mat.stat-mech #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.69.214418
20 pages; 1 figure; to appear in Physical Review B
arxiv created 2004/04/22 · openalex publication_date 2004/06/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Kondo--spin glass competition is studied in a theoretical model of a Kondo lattice with an intrasite Kondo-type exchange interaction treated within the mean-field approximation, an intersite quantum Ising exchange interaction with random couplings among localized spins, and an additional transverse field \ensuremathΓ in the x direction, which represents a simple quantum mechanism of spin flipping, in order to have a better description of the spin glass state and in particular of the quantum critical point (QCP). Taking here a parametrization \ensuremathΓ=\ensuremathαJK2 (where JK is the antiferromagnetic Kondo coupling), we obtain two second order transition lines from the spin glass state to the paramagnetic one and then to the Kondo state. For a reasonable set of the different parameters, the two second order transition lines do not intersect and end in two distinct QCPs. The existence of a QCP in the spin glass--Kondo competition allows one to give a better description of the phase diagrams of some cerium and uranium disordered alloys.