A. S. Belozerov, I. Leonov, V. I. Anisimov
We present a computational scheme for the investigation of complex materials with correlated electrons which allows one to take into account the spin rotational symmetry of the exchange Coulomb interaction. It combines {\it ab initio} band structure methods with dynamical mean-field theory and is implemented with the Hirsch-Fye quantum Monte Carlo algorithm in which the spin rotational invariance of Hund's exchange is restored by averaging over all possible directions of spin quantization axis. We employ this technique to perform benchmark calculations for the three-band Hubbard model on the infinite-dimensional Bethe lattice. Our results agree quantitatively well with those obtained using the continuous-time quantum Monte Carlo method. The proposed approach is employed to compute the electronic and magnetic properties of paramagnetic $\alpha$ iron and nickel. The obtained Curie temperatures agree well with experiment. Our results indicate that the magnetic transition temperature is significantly overestimated by using the density-density type of Coulomb interaction.
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http://arxiv.org/abs/1210.0911
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