M. S. Laad

Orbital switching and the first-order insulator-metal transition in paramagnetic V2O3

The first-order metal-insulator transition (MIT) in paramagnetic V2O3 is studied within the ab initio scheme LDA+DMFT, which merges the local density approximation (LDA) with dynamical mean field theory (DMFT). With a fixed value of the Coulomb U=6.0 eV, we show how the abrupt pressure driven MIT is understood in a new picture: a pressure-induced decrease of the trigonal distortion within the strong correlation scenario (which is not obtained within LDA). We find good quantitative agreement with (i) switch of the orbital occupation of (a(1g),e(pi)(g1),e(pi)(g2)) and the spin state S=1 across the MIT, (ii) thermodynamics and dc resistivity, and (iii) the one-electron spectral function, within this new scenario.

Orbital correlations in the ferromagnetic half-metal CrO 2

We deduce a model relevant for the description of the ferromagnetic half-metal chromium dioxide

Unconventional Mott transition in KxFe2−ySe2

({\mathrm{CrO}}_{2}),

Electron energy-loss spectroscopy of strongly correlated systems in infinite dimensions

widely used in magnetic recording technology. The model describes the effect of dynamical, local orbital correlations arising from local quantum chemistry of the material. A finite-temperature solution of the model in

Non-local effects in the fermion dynamical mean-field framework; application to the two-dimensional Falicov-Kimball model

d=\ensuremath{\infty}

Orbital Kondo effect in CrO2: a combined local-spin-density-approximation dynamical-mean-field-theory study.

provides a natural explanation of the optical response, photoemission, resistivity, and the large Woods-Saxon ratio observed in experiments. Our study confirms the important role of many-body dynamical correlation effects for a proper understanding of the metallic phase of

Effect of strong correlations and static diagonal disorder in the d = ∞ Hubbard model

{\mathrm{CrO}}_{2}.

Role of orbital degeneracy in double-exchange systems

The newly discovered 122-iron-chalcogenide superconductors show clear signatures of Mott-insulating and strange, incoherent metal normal states. Motivated thereby, we use local-density approximation plus dynamical mean-field theory (LDA + DMFT) to study the electronic structure and transport properties of K

Towards a Fully Ab-Initio Description of the Diluted Magnetic Semiconductor

{}_{x}