Kondo screening coexisting with ferromagnetic order as a possible ground state for Kondo lattice systems

• Published in: arXiv.org
• Main Authors: Li, Guang-Bin, Zhang, Guang-Ming, Lu, Yu
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 19.03.2010
• Subjects: Conduction electrons; Conductivity; Coupling; Ferromagnetism; Ground state; Long range order; Magnetic fields; Mean field theory; Phase diagrams; Physics - Strongly Correlated Electrons; Physics - Superconductivity; Screening
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0910.1902

We consider the competition between the Kondo screening effect and ferromagnetic long-range order (FLRO) within a mean-field theory of the Kondo lattice model for low conduction electron densities \(n_{c}\). Depending on the parameter values, several types of FLRO ground states are found. When \(n_{c}<0.16\), a polarized FLRO phase is dominant. For \(0.16<n_{c}<0.82\), a non-polarized FLRO phase appears in the weak Kondo coupling region; while in the intermediate coupling region the ground state corresponds to the polarized and non-polarized FLRO phases, respectively, coexisting with the Kondo screening. For a strong Kondo coupling, the product of pure Kondo singlets is the ground state. Moreover, we also find that a weak magnetic field makes the pure Kondo singlet phase vanish, while the non-polarized FLRO state with the Kondo screening spans a large area in the phase diagram.