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  - 
TY  - JOUR
A1  - Gabel, Judith
A1  - Pickem, Matthias
A1  - Scheiderer, Philipp
A1  - Dudy, Lenart
A1  - Leikert, Berengar
A1  - Fuchs, Marius
A1  - Stübinger, Martin
A1  - Schmitt, Matthias
A1  - Küspert, Julia
A1  - Sangiovanni, Giorgio
A1  - Tomczak, Jan M.
A1  - Held, Karsten
A1  - Lee, Tien–Lin
A1  - Claessen, Ralph
A1  - Sing, Michael
T1  - Toward Functionalized Ultrathin Oxide Films: The Impact of Surface Apical Oxygen
JF  - Advanced Electronic Materials
N2  - Thin films of transition metal oxides open up a gateway to nanoscale electronic devices beyond silicon characterized by novel electronic functionalities. While such films are commonly prepared in an oxygen atmosphere, they are typically considered to be ideally terminated with the stoichiometric composition. Using the prototypical correlated metal SrVO\(_{3}\) as an example, it is demonstrated that this idealized description overlooks an essential ingredient: oxygen adsorbing at the surface apical sites. The oxygen adatoms, which are present even if the films are kept in an ultrahigh vacuum environment and not explicitly exposed to air, are shown to severely affect the intrinsic electronic structure of a transition metal oxide film. Their presence leads to the formation of an electronically dead surface layer but also alters the band filling and the electron correlations in the thin films. These findings highlight that it is important to take into account surface apical oxygen or—mutatis mutandis—the specific oxygen configuration imposed by a capping layer to predict the behavior of ultrathin films of transition metal oxides near the single unit-cell limit.
KW  - transition metal oxides
KW  - correlated oxides
KW  - electronic phase transitions
KW  - photoelectron spectroscopy
KW  - thin films
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318914
SN  - 2199-160X
VL  - 8
IS  - 4
ER  -