Dynamical mean-field approach to materials with strong electronic correlations

We review recent results on the properties of materials with correlated electrons obtained within the LDA+DMFT approach, a combination of a conventional band structure approach based on the local density approximation (LDA) and the dynamical mean-field theory (DMFT). The application to four outstanding problems in this field is discussed: (i) we compute the full valence band structure of the charge-transfer insulator NiO by explicitly including the p-d hybridization, (ii) we explain the origin for the simultaneously occuring metal-insulator transition and collapse of the magnetic moment in MnO and Fe2O3, (iii) we describe a novel GGA+DMFT scheme in terms of plane-wave pseudopotentials which allows us to compute the orbital order and cooperative Jahn-Teller distortion in KCuF3 and LaMnO3, and (iv) we provide a general explanation for the appearance of kinks in the effective dispersion of correlated electrons in systems with a pronounced three-peak spectral function without having to resort to the coupling of electrons to bosonic excitations. These results provide a considerable progress in the fully microscopic investigations of correlated electron materials.Comment: 24 pages, 14 figures, final version, submitted to Eur. Phys. J. for publication in the Special Topics volume "Cooperative Phenomena in Solids: Metal-Insulator Transitions and Ordering of Microscopic Degrees of Freedom

Calcário e escória de siderurgia avaliados por análise foliar, acúmulo, e exportação de macronutrientes em cana-de-açúcar Lime and slag evaluated by leaf analysis, macronutrient accumulation and export of sugarcane

A opção de uso de materiais corretivos alternativos como as escórias de siderurgia, pode influenciar na absorção de nutrientes pela planta e, consequentemente, na diagnose foliar, acúmulo e exportação de nutrientes. Com o objetivo de estudar o efeito da aplicação de doses de escória de siderurgia e de calcário na absorção de macronutrientes pela cana-de-açúcar (variedade SP80-1842), foi instalado em janeiro de 1998, em Ituverava-SP, um experimento de campo. Aplicou-se escória de siderurgia e calcário, em quatro doses equivalentes 0; 1,23; 2,52 e 3,80 t ha-1 de CaCO3, em um Latossolo Vermelho-Amarelo distrófico, em pré-plantio na cana-planta. Determinaram-se, além da produção de colmos, as concentrações de macronutrientes na folha +3 da cana-planta e da cana-soca (aos 120 dias após a emergência dos brotos) e na parte aérea da cana-soca (aos 345 dias após a emergência dos brotos). Os materiais corretivos e as doses não alteraram a absorção de macronutrientes pela cana-de-açúcar. Houve maior acúmulo e exportação de macronutrientes de acordo com as doses de ambos corretivos. A escória de siderurgia comportou-se de modo semelhante ao calcário na nutrição da cana-de-açúcar quanto aos macronutrientes.<br>Slag can be used as an alternative for lime as soil amendment, having influence on nutrient uptake by the plant and, as a result, on leaf analysis and nutrient accumulation. To study the effect of the application of increasing rates of slag and lime stone on the uptake of macronutrients by sugar cane (variety SP 80-1842) an experiment was installed under field conditions, in January 1998, at Ituverava-SP, Brazil. Slag and limestone were applied to the sugarcane crop at planting, in four rates: 0; 1.23; 2.52 and 3.80 t ha-1 of CaCO3, using a Typic Haplorthox. In addition to the cane stalk production a verification was performed for the first and second ratoons (120 days and 345 after the emergence of the shoots, respectively). Macronutrient concentrations on the leaf +3 and in the aerial part of sugar cane for were analysed for the second cutting. Through leaf analysis data it was found that the corrective agents and rates did not modify the degree of absorption of macronutrients by the sugar cane. Slag had some effect on sugarcane evaluation, acting in a similar way in comparison to limestone, in relation to the nutrition of the plant