Related papers: Dilution effect in correlated electron system with…
The ground state of a double-exchange model for orbitally degenerate $e_g$ electrons with Jahn-Teller lattice coupling and weak disorder is found to be spatially inhomogeneous near half filling. Using a real space Monte-Carlo method we show…
The influence of correlation effects on the orbital moments for transition metals and their alloys is studied by first-principle relativistic Density Functional Theory in combination with the Dynamical Mean-Field Theory. In contrast to the…
We consider orbital magnetic field effects in a spin liquid phase of a half-filled triangular lattice Hubbard system close to the Mott transition, continuing an earlier exploration of a state with spinon Fermi surface. Starting from the…
We study a two-dimensional effective orbital superexchange model derived for strongly correlated e_g electrons coupled to t_{2g} core spins in layered manganites. One finds that the ferromagnetic and antiferromagnetic correlations closely…
Taking the orbital degeneracy of $e_g$ conduction bands and the Coulomb interaction into account in a double-exchange model, we investigate charge dynamics of perovskite Mn oxides by the Lancz$\ddot{\rm o}$s diagonalization method. In the…
We describe a numerical approach to modeling magnetoelectric effects generated by spin-orbit coupling in inhomogeneous diffusive 2D superconductors. It is based on direct minimization of the free energy of diffusion modes, including their…
Orbital and spin ordering phenomena in strongly correlated systems are commonly studied using the local-density approximation + dynamical mean-field theory approach. Typically, however, such simulations are restricted to simplified models…
Spin-orbit coupling introduces chirality into electronic structure. This can have profound effects on the magnetization induced by orbital motion of electrons. Here we derive a formula for the orbital magnetization of interacting electrons…
The influence of configurational disorder on the magnetic properties of diluted Heisenberg spin systems is studied with regard to the ferromagnetic stability of diluted magnetic semiconductors. The equation of motion of the magnon Green's…
Dielectric and magnetic phenomena in spin and charge frustrated system RFe2O4 (R is a rare-earth metal ion) are studied. An electronic model for charge, spin and orbital degrees in a pair of triangular-lattice planes is derived. We analyze…
On the example of monolayer manganites we show that the theoretical ideas developed long ago along the derivation of the spin t-J model from the Hubbard model are nowadays very helpful in strongly correlated oxides with partly filled…
We have studied the phase diagram and excitations of the spin-orbital model derived for a three dimensional perovskite lattice, as in KCuF_3. The results demonstrate that the orbital degeneracy drastically increases quantum fluctuations and…
The role of orbital ordering on metal-insulator transition of transition-metal oxides is investigated by the cluster self-consistent field approach in the strong correlation regime. A clear dependence of the insulating gap on the orbital…
We present the results of our theoretical study on the effects of geometrical frustration and the interplay between spin and orbital degrees of freedom in vanadium spinel oxides $A$V$_2$O$_4$ ($A$ = Zn, Mg or Cd). Introducing an effective…
Recent measurements on MgV$_2$O$_4$ single crystal have reignited the debate on the role of spin-orbit (SO) coupling in dictating the orbital order in Vanadium spinel systems. Density functional theory calculations were performed using the…
We study the symmetry-broken phases in two- and three-orbital Hubbard models with lifted orbital degeneracy using dynamical mean field theory. On the technical level, we explain how symmetry relations can be exploited to measure the…
We study a doubly-degenerate orbital model on a honeycomb attice. This is a model for orbital states in multiferroic layered iron oxides. The classical and quantum models are analyzed by spin-wave approximation, Monte-Carlo simulation and…
We review some aspects related to orbital degrees of freedom in manganites. The Mn$^{3+}$ ions in these compounds have double orbital degeneracy and are strong Jahn-Teller ions, causing structural distortions and orbital ordering. We…
Recent optical conductivity $\sigma(\omega)$ experiments have revealed an anomalous spectral distribution in the ferromagnetic phase of the perovskite system $La_{1-x}Sr_xMnO_3$. Using finite temperature diagonalization techniques we…
To understand effects of orbital degeneracy on magnetism, in particular effects of Hund's rule coupling, we study the two-orbital Hubbard model on a square lattice by a variational Monte Carlo method. As a variational wave function, we…