Modified Equation of Motion Approach for Ferromagnetic Systems
G. Górski, J. Mizia and K. Kucab
Faculty of Mathematics and Natural Sciences, University of Rzeszów, S. Pigonia 1, 35-310 Rzeszów, Poland
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The key problem in using the dynamical mean-field theory is finding the appropriate solution to the single impurity Anderson model. We use the modified equation of motion method based on differentiation over two time variables. In such approach we obtain correct description of the Kondo effect not only for systems symmetrical with respect to the half-filled point but also for the systems without symmetry in a half filled point and for broad range of electron concentrations like e.g. the ferromagnetic systems. For the reason of these advantages we investigate in this report dependence of the system magnetic moment on carrier concentration using our modified equation of motion method. We also analyze influence of asymmetric densities of states on ferromagnetic alignment. Our results are compared with dynamical mean-field theory-quantum Monte Carlo calculations and with Hubbard I and III approximations.

DOI: 10.12693/APhysPolA.127.207
PACS numbers: 71.10.Fd, 75.10.Lp, 75.30.Kz