Regensburg 2007 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 26: Metal-Insulator Transition

TT 26.1: Talk

Thursday, March 29, 2007, 14:00–14:15, H19

Local correlations and hole doping in NiO — •Jan Kunes¹, Vladimir I. Anisimov², Alexey V. Lukoyanov³, and Dieter Vollhardt¹ — ¹Theoretical Physics III, Center for Electronic Correlations and Magnetism, University of Augsburg, Augsburg 86135 — ²nstitute of Metal Physics, Russian Academy of Sciences - Ural Division, 620041 Yekaterinburg GSP-170, Russia — ³Ural State Technical University - UPI, 620002 Yekaterinburg, Russia

Charge-transfer (CT) insulators present an important subgroup of transition metal compounds which exhibit phenomena such as metal-insulator transitions or high temperature superconductivity. The location of ligand states between the interaction-split d bands leads to additional complexity, which requires a description beyond a simple Hubbard model. Using a combination of ab initio bandstructure and dynamical mean field theory (DMFT) we study the prototypical CT insulator NiO. Including the ligand p orbitals to the effective Hamiltonian, we obtain good agreement with PES and IPES data. Further we investigate the effect of hole doping. We find the additional holes to occupy mainly the ligand p orbitals despite large Ni-d spectral weight at the top of the valence band. Moreover, heavy hole doping leads to a significant reconstruction of the single-particle spectrum and filling of the charge-transfer gap. This is the first LDA+DMFT study of charge transfer systems, which includes the p-d hybridization explicitly and is thus able to provide a full description of valence and conduction band spectra.