Spiral magnetic phases on the Kondo Lattice Model: A Hartree-Fock approach

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:423

Article

Costa, N. C.^1,2  Lima, J. P.²  dos Santos, Raimundo R.¹ 

[1] Univ Fed Rio Janeiro, Inst Fisica, Rio De Janeiro, RJ, Brazil

[2] Univ Fed Piaui, Dept Fisica, Teresina, Brazil

关键词: Magnetism;    Kondo lattice;    Mean-field;    Hartree-Fock approximation;   

DOI  :  10.1016/j.jmmm.2016.09.061

来源: Elsevier

【 摘 要 】

We study the Kondo Lattice Model (KLM) on a square lattice through a Hartree-Fock approximation in which the local spins are treated semi-classically, in the sense that their average values are modulated by a magnetic wavevector Q while they couple with the conduction electrons through fermion operators. In this way, we obtain a ground state phase diagram in which spiral magnetic phases (in which the wavevector depends on the coupling constants and on the density) interpolate between the low-density ferromagnetic phase and the antiferromagnetic phase at half filling; within small regions of the phase diagram commensurate magnetic phases can coexist with Kondo screening. We have also obtained `Doniach-like' diagrams, showing the effect of temperature on the ground state phases, and established that for some ranges of the model parameters (the exchange coupling and conduction electron density) the magnetic wavevector changes with temperature, either continuously or abruptly (e. g., from spiral to ferromagnetic).

【 授权许可】

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