Erik Koch

Mott transition in degenerate Hubbard models: Application to doped fullerenes.

The Mott-Hubbard transition is studied for a Hubbard model with orbital degeneracy

Metal-insulator transitions: Influence of lattice structure, Jahn-Teller effect, and Hund's rule coupling

N

Mechanism for orbital ordering in KCuF3.

, using a diffusion Monte Carlo method. Based on general arguments, we conjecture that the Mott-Hubbard transition takes place for

MOTT-HUBBARD INSULATORS FOR SYSTEMS WITH ORBITAL DEGENERACY

\frac{U}{W}\ensuremath{\sim}\sqrt{N}

Screening, Coulomb Pseudopotential, and Superconductivity in Alkali-Doped Fullerenes

, where

Electron-phonon interaction and antiferromagnetic correlations.

U

Importance of exchange-anisotropy and superexchange for the spin-state transitions in LnCoO3 (Ln=La,Y,RE) cobaltates

is the Coulomb interaction and

Static versus dynamical mean-field theory of Mott antiferromagnets

W

Renormalization of the electron-phonon coupling in the one-band Hubbard model

is the bandwidth. This is supported by exact-diagonalization and Monte Carlo calculations. Realistic parameters for the doped fullerenes lead to the conclusions that stoichiometric

Role of alkali atoms in A 4 C 60

{A}_{3}{\mathrm{C}}_{60}(A=\mathrm{K},\phantom{\rule{0ex}{0ex}}\mathrm{R}\mathrm{b})