Related papers: Origin of the Magnetic and Orbital ordering in $\a…
Based on density functional calculations, we propose a possible orbital ordering in MnV2O4 which consists of orbital chains running along crystallographic a and b directions with orbitals rotated alternatively by about 45 degrees within…
We used femtosecond optical spectroscopy to study ultrafast spin and orbital ordering dynamics in the antiferromagnetic Mott insulator $\alpha$-Sr$_2$CrO$_4$. This chromate system possesses multiple spin and orbital ordered phases, and…
The alloy Ca$_{2-x}$Sr$_x$RuO$_4$ exhibits a complex phase diagram with peculiar magnetic metallic phases. In this paper some aspects of this alloy are discussed based on a mean field theory for an effective Kugel-Khomskii model of…
Neutron inelastic scattering and diffraction techniques have been used to study the MnV2O4 spinel system. Our measurements show the existence of two transitions to long-range ordered ferrimagnetic states; the first collinear and the second…
Alkali superoxides differ from conventional transition metal magnets, exhibit magnetism from partially occupied oxygen molecular $\pi^*$-orbitals. Among them, CsO$_2$ stands out for its potential to exhibit novel quantum collective…
In strongly correlated electronic systems, several novel physical properties are induced by the orbital degree of freedom. In particular, orbital degeneracy near the Fermi level leads to spontaneous symmetry breaking, such as the nematic…
In contrast to the previous reports that the divalent perovskite SrCrO$_3$ was believed to be cubic structure and nonmagnetic metal, recent measurements suggest coexistence of majority tetragonally distorted weak antiferromagnetic phase and…
Charge and orbital ordering in the low-temperature monoclinic structure of magnetite (Fe_3O_4) is investigated using LSDA+U. While the difference between t_{2g} minority occupancies of Fe^{2+}_B and Fe^{3+}_B cations is large and gives…
Spin wave excitations and stability of the ($\pi,0$) ordered magnetic state are investigated in a minimal two-band itinerant-electron model for iron pnictides. Presence of hopping anisotropy generates a strong ferro-orbital order in the…
The two-orbital double-exchange model is employed for the study of the magnetic and orbital orders in ($R$MnO$_3$)$_n$/($A$MnO$_3$)$_{2n}$ ($R$: rare earths; $A$: alkaline earths) superlattices. The A-type antiferromagnetic order is…
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 attribute the structural phase transition (SPT) in the parent compounds of the iron pnictides to orbital ordering. Due to the anisotropy of the $d_{xz}$ and $d_{yz}$ orbitals in the $xy$ plane, a ferro-orbital ordering makes the…
Toroidal order, given by a composite of electric and magnetic orders, manifests itself not only in the peculiar magnetism but also in anomalous transport and magnetoelectric effect. We report our theoretical results on the influence and…
We introduce the concept of \emph{orbital altermagnetism}, a symmetry-protected magnetic order of pure orbital degrees of freedom. It is characterized with ordered anti-parallel orbital magnetic moments in real space but momentum-dependent…
The one-particle spectral function and its orbital composition are investigated in a three-orbital model for the undoped parent compounds of the iron-based superconductors. In the realistic parameter regime, where results best fit…
MgV$_{2}$O$_{4}$ is a spinel based on magnetic V$^{3+}$ ions which host both spin ($S=1$) and orbital ($l_{eff}=1$) moments. Owing to the underlying pyrochlore coordination of the magnetic sites, the spins in MgV$_{2}$O$_{4}$ only…
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…
We propose the origin of the charge-ordered stripe structure with the orbital ordering observed experimentally in La_(1-x)Ca_(x)MnO_(3) (x=1/2, 2/3), in which the long-range Coulomb interaction plays an essential role. We study a Hubbard…
We develop an understanding of the anomalous metal state of the parent compounds of recently discovered iron based superconductors starting from a strong coupling viewpoint, including orbital degrees of freedom. On the basis of an…
{\it Ab-initio} studies of the stability of orbital ordering, its coupling to magnetic structure and its possible origins (electron-phonon and/or electron-electron interactions) are reported for two perovskite systems, LaMnO$_3$ and…