Related papers: Dilution effect in correlated electron system with…
Systems of highly degenerate ordered or frozen state may exhibit inverse melting (reversible crystallization upon heating) or inverse freezing (reversible glass transition upon heating). This phenomena is reviewed, and a list of…
The ground state properties and the thermodynamics of the one-dimensional SU(4) symmetric spin system with orbital degeneracy are investigated using the quantum Monte Carlo loop algorithm. The spin-spin correlation functions exhibit a…
We investigate the interplay between spin and orbital correlations in monolayer and bilayer manganites using an effective spin-orbital t-J model which treats explicitly the e_g orbital degrees of freedom coupled to classical t_{2g} spins.…
The concept of the entanglement between spin and orbital degrees of freedom plays a crucial role in understanding various phases and exotic ground states in a broad class of materials, including orbitally ordered materials and spin liquids.…
We discuss spin and orbital ordering in the twofold orbital degenerate superexchange model in three dimensions relevant to perovskite transition metal oxides. We focus on the particular point on the classical phase diagram where orbital…
In the Mott insulating phase of the transition metal oxides, the effective orbital-orbital interaction is directional both in the orbital space and in the real space. We discuss a classical realization of directional coupling in two…
We study the effect in geometrically frustrated antiferromagnets of weak, random variations in the strength of exchange interactions. Without disorder the simplest classical models for these systems have macroscopically degenerate ground…
The magnetoelectric effect has been actively studied in multiferroics since the first observation in an antiferromagnetic, $\mathrm{Cr_2O_3}$. This effect appears in systems without spatial inversion symmetry and time-reversal symmetry and…
We present a study of the magnetic-field effect on spin correlations in the charge ordered triangular Ising system LuFe2O4+{\delta} through single crystal neutron diffraction. In the absence of a magnetic field, the strong diffuse neutron…
In this paper we study the orbital weak-field susceptibility of two-dimensional diffusive mesoscopic systems. For the previously unstudied regime of temperatures lower than the mean level spacing we find unexpected strong temperature as…
The influence of substitutional disorder on the magnetic properties of diluted Heisenberg spin systems is studied with regard to the magnetic stability of ferromagnetic diluted semiconductors (DMS). The equation of motion for the magnon…
We study a two-dimensional single band Hubbard Hamiltonian with antisymmetric spin-orbit coupling. We argue that this is the minimal model to understand the electronic properties of locally non-centrosymmetric transition-metal (TM) oxides…
Motivated by recent experiments on Mott insulators, in both iridates and ultracold atoms, we theoretically study the effects of magnetic order on the Mott-Hubbard excitons. In particular, we focus on spin-mediated doublon-holon pairing in…
We study the magnetic field effects on the diluted spin-ice materials using the replica-exchange Monte Carlo simulation. We observe five plateaus in the magnetization curve of the diluted nearest-neighbor spin-ice model on the pyrochlore…
We consider small ballistic quantum dots weakly coupled to the leads in the chaotic regime and look for significant spin-orbit effects. We find that these effects can become quite prominent in the vicinity of degeneracies of many-body…
In this work we present a theoretical investigation into an antiferromagnetically coupled spin system, specifically ${\rm Cu}_{3}-X$ ($\mathrm{X=As,Sb}$), which exhibits an isosceles triangular configuration or slightly distorted…
We discuss the ground state of the spin-orbital model for spin-one ions with partially filled $t_{2g}$ levels on a honeycomb lattice. We find that the orbital degrees of freedom induce a spontaneous dimerization of spins and drive them into…
We present a theoretical study of diluted magnetic semiconductors that includes spin-orbit coupling within a realistic host band structure and treats explicitly the effects of disorder due to randomly substituted Mn ions. While spin-orbit…
Phase diagram of half-doped perovskite manganites is studied within the extended double-exchange model. To demonstrate the role of orbital degrees of freedom both one- and two-orbital models are examined. A rich phase diagram is obtained in…
Spin-crossover compounds, which are characterized by magnetic ions showing low-spin and high-spin states at thermally accessible energies, are ubiquitous in nature. We here focus on the effect of an exchange interaction on the collective…