Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Correlated Electrons: Poster Session
TT 32.80: Poster
Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B
Ferromagnetism in the multi-orbital periodic Anderson model — •Unjong Yu, Krzysztof Byczuk, and Dieter Vollhardt — Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute for Physics, University of Augsburg, D-86135 Augsburg, Germany
At less than half-filling the localized f-electrons of the periodic Anderson model (PAM) can order ferromagnetically already at moderate values of the Coulomb repulsion U [1]. In the case of disorder in the f-level the corresponding critical temperature TC always decreases [2,3]. By contrast, disorder in the conduction electrons can give rise to a surprisingly rich non-monotonic dependence of TC [3]. Here we present results of the first investigation of the influence of band-degeneracy of the conduction- and/or f-electrons on the stability of the ferromagnetic phase of the PAM. In particular, a remarkable increase of TC with the degeneracy in the localized levels is found. The origin of this increase and other features will be discussed.
[1] A. N. Tahvildar-Zadeh, M. Jarrell, and J. K. Freericks,
Phys. Rev. B 55, R3332 (1997).
[2] D. Meyer, Solid State Commun. 121, 565 (2002).
[3] U. Yu, K. Byczuk, and D. Vollhardt, "Effect of Disorder
on Ferromagnetism in the Periodic Anderson Model", in preparation.