TY  - JOUR
A1  - Hausoel, A.
A1  - Karolak, M.
A1  - Şaşιoğlu, E.
A1  - Lichtenstein, A.
A1  - Held, K.
A1  - Katanin, A.
A1  - Toschi, A.
A1  - Sangiovanni, G.
T1  - Local magnetic moments in iron and nickel at ambient and Earth's core conditions
JF  - Nature Communications
N2  - Some Bravais lattices have a particular geometry that can slow down the motion of Bloch electrons by pre-localization due to the band-structure properties. Another known source of electronic localization in solids is the Coulomb repulsion in partially filled d or f orbitals, which leads to the formation of local magnetic moments. The combination of these two effects is usually considered of little relevance to strongly correlated materials. Here we show that it represents, instead, the underlying physical mechanism in two of the most important ferromagnets: nickel and iron. In nickel, the van Hove singularity has an unexpected impact on the magnetism. As a result, the electron–electron scattering rate is linear in temperature, in violation of the conventional Landau theory of metals. This is true even at Earth’s core pressures, at which iron is instead a good Fermi liquid. The importance of nickel in models of geomagnetism may have therefore to be reconsidered.
KW  - ferromagnetism
KW  - electronic properties and materials
KW  - magnetic properties and materials
KW  - nickel
KW  - iron
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170681
VL  - 8
IS  - 16062
ER  - 
TY  - JOUR
A1  - Hansmann, P.
A1  - Parragh, N.
A1  - Toschi, A.
A1  - Sangiovanni, G.
A1  - Held, K.
T1  - Importance of d-p Coulomb interaction for high T-C cuprates and other oxides
JF  - New Journal of Physics
N2  - Current theoretical studies of electronic correlations in transition metal oxides typically only account for the local repulsion between d-electrons even if oxygen ligand p-states are an explicit part of the effective Hamiltonian. Interatomic interactions such as U-pd between d- and (ligand) p-electrons, as well as the local interaction between p-electrons, are neglected. Often, the relative d-p orbital splitting has to be adjusted 'ad hoc' on the basis of the experimental evidence. By applying the merger of local density approximation and dynamical mean field theory to the prototypical case of the three-band Emery dp model for the cuprates, we demonstrate that, without any 'ad hoc' adjustment of the orbital splitting, the charge transfer insulating state is stabilized by the interatomic interaction U-pd. Our study hence shows how to improve realistic material calculations that explicitly include the p-orbitals.
KW  - correlated electrons
KW  - dynamical mean field theory
KW  - transition metal oxides
KW  - fermions
KW  - superconductivity
KW  - energy bands
KW  - transition metals
KW  - correlated systems
KW  - mean-field theory
KW  - electronic-structure calculations
KW  - inplane spectral weight
KW  - Hubbard model
KW  - infinite dimensions
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117165
SN  - 1367-2630
VL  - 16
IS  - 33009
ER  -