Band Calculation for Ce-Compounds on the basis of Dynamical Mean Field Theory
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The band calculation scheme for f electron compounds is developed on the basis of the dynamical mean field theory (DMFT) and the LMTO method. The auxiliary impurity problem is solved by a method named as NCAf2v’, which includes the correct exchange process of the f1→f2 virtual excitation as the vertex correction to the non-crossing approximation (NCA) for the f1→f0 fluctuation. This method leads to the correct magnitude of the Kondo temperature, TK, and makes it possible to carry out quantitative DMFT calculation including the crystalline field (CF) and the spin–orbit (SO) splitting of the self-energy. The magnetic excitation spectra are also calculated to estimate TK. It is applied to Ce metal and CeSb at T=300 K as the first step. In Ce metal, the hybridization intensity (HI) just below the Fermi energy is reduced in the DMFT band. The photo-emission spectra (PES) have a conspicuous SO side peak, similar to that of experiments. TK is estimated to be about 70 K in γ-Ce, while to be about 1700 K in α-Ce. In CeSb, the double-peak-like structure of PES is reproduced. The HI is enhanced just at the Fermi energy in the DMFT band of CeSb. Therefore, TK∼60 K, which is comparable to but slightly larger than the experimental value, is obtained.
- Journal of the Physical Society of Japan
Journal of the Physical Society of Japan 74 (9), 2517-2529, 2005
THE PHYSICAL SOCIETY OF JAPAN