相关论文: Orbital ordering and frustrations
Coexistence of various ordered chaotic states in a Hamiltonian system is studied with the use of a symplectic coupled map lattice. Besides the clustered states for the attractive interaction, a novel chaotic ordered state is found for a…
Dilution effects on the long-range ordered state of the doubly degenerate $e_g$ orbital are investigated. Quenched impurities without the orbital degree of freedom are introduced in the orbital model where the long-range order is realized…
First-order structural phase transition is a common phenomenon in materials that qualitatively alters their physical properties. Yet, the abrupt first-order nature is usually unexplained by realistic computations, implying an omission of…
Magnetic and orbital structures in KCuF$_{3}$ are revisited by the cluster self-consistent field approach developed recently. We clearly showed that due to the inherent frustration, the ground state of the system with the superexchange and…
We study ordering mechanisms which are induced by the quantum fluctuation in fully frustrated Ising spin systems. Since there are many degenerated states in frustrated systems, "order by thermal disorder" often takes place due to a kind of…
How do topological defects affect the degree of order in active matter? To answer this question we investigate an agent-based model of self-propelled particles, which accounts for polar alignment and short-ranged repulsive interactions. For…
Magnetic and other unconventional electronic orders are discussed for heavy electrons. In addition to the ordinary Kondo lattice, we consider non-Kramers systems taking the two-channel Kondo lattice, and another lattice that consists of a…
The Jahn-Teller distortive transition of \lmo is described by a modified 3-state Potts model. The interactions between the three possible orbits depends both on the orbits and their relative orientation on the lattice. Values of the two…
We study critical and magnetic properties of a bilayer Ising system consisting of two triangular planes A and B, with the antiferromagnetic (AF) coupling $J_{\rm A}$ and the ferromagnetic (FM) one $J_{\rm B}$ for the respective layers,…
We analyze electronic, magnetic, and structural properties of the spinel compound MgTi$_2$O$_4$ using the local density approximation+U method. We show how MgTi$_2$O$_4$ undergoes to a canted orbital-spin ordered state, where charge, spin…
A mixture of light and heavy spin-polarized fermionic atoms in an optical lattice is considered. Tunneling of the heavy atoms is neglected such that they are only subject to thermal fluctuations. This results in a complex interplay between…
Phase separation of sequence-disordered liquid crystalline polymers, a promising class of technological and biological relevance, is studied by field theory, and thermodynamic mechanisms responsible for orientational ordering observed in…
The functional properties of transition metal perovskite oxides are known to result from a complex interplay of magnetism, polarization, strain, and stoichiometry. Here, we show that for materials with a cooperative Jahn-Teller distortion,…
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…
The candidate magnetoelectric Pb3Mn7O15 has a structure consisting of 1/3 filled Kagome layers linked by ribbons of edge-sharing octahedra in the stacking direction. Previous reports have indicated a complex hexagonal-orthorhombic…
The average structure of the solid solution LaMn$_{1-x}$Ga$_x$O$_3$ (LMGO) has been investigated from a symmetry-motivated approach utilizing synchrotron x-ray and neutron powder diffraction techniques. We show experimentally that a…
The stable magnetisation configurations of antiferromagnets on quasiperiodic tilings are investigated theoretically. The exchange coupling is assumed to decrease exponentially with the distance between magnetic moments. It is demonstrated…
We study the renormalization of magnons by charge and coupled orbital-lattice fluctuations in colossal magnetoresistance compounds. The model considered is an orbitally degenerate double-exchange system coupled to Jahn-Teller active…
We explore the magnetic phases in a Kondo lattice model on the geometrically frustrated Shastry-Sutherland lattice at metallic electron densities, searching for noncollinear and noncoplanar spin textures. Motivated by experimental…
A systematic study of the electronic structure in perovskite manganites is presented. The effective Hamiltonian is derived by taking into account the degeneracy of $e_g$ orbitals and strong electron correlation in Mn ions. The spin and…