Related papers: Orbital order and fluctuations in Mott insulators
Different types of order are discussed in the context of strongly correlated transition metal oxides, involving pure compounds and $3d^{3}-4d^{4}$ and $3d^{2}-4d^{4}$ hybrids. Apart from standard, long-range spin and orbital orders we…
By combining first-principles electronic-structure calculations with the model Hamiltonian approach, we systematically study the magnetic properties of sodium superoxide (NaO2), originating from interacting superoxide molecules. We show…
Spin-state ordering - a periodic pattern of ions with different spin-state configurations along a crystal lattice - is a rare phenomenon, and its possible interrelation with other electronic degrees of freedom remains little explored. Here…
In order to study the interplay between localized and dispersive orbital states in a system of ultracold atoms in an optical lattice, we investigate the possibility to coherently couple the lowest two Bloch bands by means of resonant…
The crystallographic and magnetic phase diagram of the n=2 layered manganite La2-2xSr1+2xMn2O7 in the region x=>0.5 has been studied using temperature dependent neutron powder diffraction. The magnetic phase diagram reveals a progression of…
We have theoretically studied successive transitions in vanadium spinel oxides with (t_2g)^2 electron configuration. These compounds show a structural transition at ~ 50K and an antiferromagnetic transition at ~ 40K. Since threefold t_2g…
We report high resolution neutron scattering measurements on the triangular lattice Mott insulator Na$_x$CrO$_2$ ($x$=1) which has recently been shown to exhibit an unusually broad fluctuating crossover regime extending far below the onset…
Transition metal oxides are a rich group of materials with very interesting physical properties that arise from the interplay of the charge, spin, orbital, and lattice degrees of freedom. One interesting consequence of this, encountered in…
LaCoO$_3$ provides a poignant example of a transition metal oxide where the cobalt cations display multiple spin states and spin transitions and which continues to garner substantial attention. In this work, we describe first principles…
Highly disordered magnetism confined to individual weakly interacting vortices is detected by muon spin rotation in two different families of high-transition-temperature superconductors, but only in samples on the low-doping side of the…
The intertwined charge, spin, orbital, and lattice degrees of freedom could endow 5d compounds with exotic properties. Current interest is focused on electromagnetic interactions in these materials, whereas the important role of lattice…
We investigate the importance of quantum orbital fluctuations in the orthorhombic and monoclinic phases of the Mott insulators LaVO3 and YVO3. First, we construct ab-initio material-specific t2g Hubbard models. Then, by using dynamical…
We have analyzed the symmetry properties and the ground state of an orbital Hubbard model with two orbital flavors, describing a partly filled spin-polarized $e_g$ band on a cubic lattice, as in ferromagnetic manganites. We demonstrate that…
The (SrTiO$_3$)$_m$/(SrVO$_3$)$_n$ $d^0-d^1$ multilayer system is studied with first principles methods through the observed insulator-to-metal transition with increasing thickness of the SrVO$_3$ layer. When correlation effects with…
The collective behavior of correlated electrons in the VO$_2-$interface layer of LaVO$_3$/SrTiO$_3$ heterostructure is studied within a quarter-filled $t_{2g}$-orbital Hubbard model on a square lattice. We argue that the ground state is…
Multiorbital correlated materials are often on the verge of multiple electronic phases (metallic, insulating, super- conducting, charge and orbitally ordered), which can be explored and controlled by small changes of the external…
Several spin systems with low dimensionality develop a spin-dimer phase within a molecular orbital below TS, competing with long-range antiferromagnetic order. Very often, preferential orbital occupancy and ordering are the actual driving…
Interaction-driven metal-insulator transitions or Mott transitions are widely observed in condensed-matter systems. In multi-orbital systems, many-body physics is richer in which an orbital-selective metal-insulator transition is an…
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…
We consider a model of strongly correlated $e_g$ electrons interacting by superexchange orbital interactions in the ferromagnetic phase of LaMnO$_3$. It is found that the classical orbital order with alternating occupied $e_g$ orbitals has…