Curie-Weiss susceptibility in strongly correlated electron systems


The magnetism of solids is macroscopic evidence of microscopic quantum dynamics of spins of valence electrons. Magnetic susceptibility of metals with delocalized conduction electrons should theoretically be of Pauli character. However, the transition metals react on the magnetic field via the Curie-Weiss law due to local magnetic moments. We succeeded in identifying a microscopic mechanism combining adequately quantum and thermal fluctuations in metals with strong electron correlations that lead to the genesis of local magnetic moments and the Curie-Weiss susceptibility.

Teoretická předpověď a numerická simulace Curieho-Weissovy susceptibility
Temperature dependence of the product of temperature T and magnetic susceptibility χ, the constant value of which reflects the Curie-Weiss law, determined from our analytic theory, left panel, and from Monte-Carlo simulations, right panel, for the single-impurity Anderson model. Here Δ is the width of the band of the conduction electrons, and U is the strength of electron correlations. Both results prove the existence of the Curie-Weiss susceptibility for sufficiently strong electron correlations in a temperature interval above the Kondo temperature below which the susceptibility goes over to the Pauli one, and the plotted curves must fall to zero. The analytic theory predicts qualitatively correctly the universal character of the Curie-Weiss susceptibility but misses the nonuniversal numerical value of the Curie constant.

Contact person: Václav Janiš