相关论文: Randomly Diluted e_g Orbital-Ordered Systems

Coupling between different degrees of freedom (DOF) in an electronic material leads to exotic phases of matter characterized by complex and competing order parameters as well as emergent excitations. Building a microscopic understanding of…

An orbital ordering occurs in many transition metal compounds with Jahn-Teller ions and plays an important role in these materials. At the same time, exchange interactions in orbitally degenerate systems are inherently frustrated, even in…

We study the low-temperature properties of the classical three-dimensional compass or $t_{2g}$ orbital model on simple-cubic lattices by means of comprehensive large-scale Monte Carlo simulations. Our numerical results give evidence for a…

A stochastic second-order wave model is applied to assess the statistical properties of wave orbital velocity in random sea states below the water surface. Directional spreading effects as well as the dependency of the water depth are…

In this review we consider glass states of several disordered systems: vortices in impure superconductors, amorphous magnets, and nematic liquid crystals in random porous media. All these systems can be described by the random-field or…

We study the effects of temperature and magnetic field on a two-orbital Hubbard model within dynamical mean field theory. We focus on the quarter filled system, which is a special point in the phase diagram due to orbital degeneracy. At…

We demonstrate the feasibility of performing sufficient configurational sampling of disordered oxides directly from first principles without resorting to the use of fitted models such as cluster expansion. This is achieved by harnessing the…

We study the effect of thermal fluctuations in the XY-model on a surface with non vanishing mean curvature and zero Gaussian curvature. Unlike Gaussian curvature that typically frustrates orientational order, the extrinsic curvature of 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 present a general formula of the orbital magnetization of disordered systems based on the Keldysh Green's function theory in the gauge-covariant Wigner space. In our approach, the gauge invariance of physical quantities is ensured from…

We calculate numerically the periodic orbits of pseudointegrable systems of low genus numbers $g$ that arise from rectangular systems with one or two salient corners. From the periodic orbits, we calculate the spectral rigidity…

We study the collective dynamics of repulsive self-propelled particles. The particles are governed by coupled equations of motion that include polar self-propulsion, damping of velocity and of polarity, repulsive particle-particle…

In a large number of rare-earth and actinide systems, Kondo effect tends to suppress magnetic order by making the spin singlet between localized and conduction electron spins. In the presence of orbital degrees of freedom, however, there…

Basic mechanisms controlling orbital order and orbital fluctuations in transition metal oxides are discussed. The lattice driven classical orbital picture, e.g. like in manganites LaMnO$_3$, is contrasted to the quantum behavior of orbitals…

We investigate the Kondo effect in two-dimensional disordered electron systems using a finite-temperature quantum Monte Carlo method. Depending on the position of a magnetic impurity, the local moment is screened or unscreened by the spin…

In this paper I give a short review of some properties of the colossal magnetoresistance manganites, connected with the orbital degrees of freedom. Ions Mn{3+}, present in most of these compounds, have double orbital degeneracy and are…

We consider doping of non-magnetic impurities in the spin-1/2, 1/5-depleted square lattice. This structure, whose undoped phase diagram offers both magnetically ordered and spin-liquid ground states, is realized physically in CaV_4O_9.…

Counterintuitive order-disorder phenomena emerging in antiferromagnetically coupled spin systems have been reported in various studies. Here we perform a systematic effective field theory analysis of two-dimensional bipartite quantum…

We study the Kondo effect and related transport properties in orbitally degenerate vertical quantum dot systems with plural electrons. Applying the non-crossing approximation to the three-orbital Anderson impurity model with the finite…

We report on the results of molecular dynamics simulation (MD) studies of the classical two-dimensional electron crystal in the presence disorder. Our study is motivated by recent experiments on this system in modulation doped semiconductor…