2000/04/06 by Guang-Ming Zhang, Qiang Gu, Lu Yu · 1 citation
Physics and Astronomy · #Anderson impurity model #Condensed matter physics #Electron #Excited state #Kondo effect #Kondo insulator #Kondo model #Lattice (music) #Monte Carlo method #Phase transition #Physics #Physics of Superconductivity and Magnetism #Quantum Monte Carlo #Quantum and electron transport phenomena #Quantum mechanics #Quantum phase transition #Quantum spin liquid #Rare-earth and actinide compounds #Singlet state #Spin (aerodynamics) #Spin polarization #Spins #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.62.69
Revtex, four pages, three figures; to be published in Physical Review B1, 1 July (2000)
arxiv created 2000/04/06 · openalex publication_date 2000/07/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A simplified version of the symmetric Kondo lattice model, the Kondo necklace model, is studied by using a representation of impurity and conduction electron spins in terms of local Kondo singlet and triplet operators. Within a mean-field theory, a spin gap always appears in the spin triplet excitation spectrum in one dimension (1D), leading to a Kondo spin liquid state for any finite values of coupling strength t/J (with t as hopping and J as exchange); in 2D and 3D cubic lattices the spin gaps are found to vanish continuously around (t/J)c\ensuremath≈0.70 and (t/J)c\ensuremath≈0.38, respectively, where quantum phase transitions occur and the Kondo spin liquid state changes into an antiferromagnetically long-range ordered state. These results are in agreement with variational Monte Carlo, higher-order series expansion, and recent quantum Monte Carlo calculations for the symmetric Kondo lattice model.