相关论文: The Jahn-Teller theorem for 3d ions and their comp…
Structure with orbital degeneracy is unstable toward spontaneous distortion. Such orbital correlation usually has a much higher energy scale than spins, and therefore, magnetic transition takes place at a much lower temperature, almost…
The crystal and magnetic structure of LaTiO3 ~ has been studied by x-ray and neutron diffraction techniques using nearly stoichiometric samples. We find a strong structural anomaly near the antiferromagnetic ordering, T$_N$=146 K. In…
Our success in description of recent electron-spin-resonance results on Mott insulator LaCoO3, Phys. Rev. B 67 (2003) 172401, lies in taking into account strong electron correlations among d electrons and the relativistic spin-orbit…
It is argued that the V3+ ion in V2O3 should be considered as described by quantum numbers S=1 and L=3. It results from Hund's rules and means that the two d electrons form the highly- correlated electron system with the importance of the…
A systematic study using neutron diffraction and magnetic susceptibility are reported on Mn substituted ferrimagnetic inverse spinel Ti$_{1-x}$Mn$_{x}$Co$_2$O$_4$ in the temperature interval 1.6 K $\leq$ $T$ $\leq$ 300 K. Our neutron…
Jahn-Teller (JT) electron-phonon coupling effects in the colossal magnetoresistance perovskite compounds $La_{1-x}A_xMnO_3$ are investigated. Electron-electron correlations between two degenerate Mn $e_g$ orbitals are studied in the…
We present an analytical calculation of the spin-wave spectrum of the Jahn-Teller system LaTiO3. The calculation includes all superexchange couplings between nearest-neighbor Ti ions allowed by the space-group symmetries: The isotropic…
To efficiently manipulate magnetism is a key physical issue for modern condensed matter physics, which is also crucial for magnetic functional applications. Most previous relevant studies rely on the tuning of spin texture, while the spin…
Three fundamentally different electronic structures for 3d electron states in LaMnO3, discussed in the current literature, have been presented. We are in favour of the localized electron atomic-like crystal-field approach that yields the…
The structural and magnetic anomaly of the layered compound SrFeO$_{2}$ were examined by first principles density functional calculations and Monte Carlo simulations. The down-spin Fe 3$d$ electron occupies the $d_{z^2}$ level rather than…
The nature of the cooperative Jahn-Teller (JT) transition accompanied by orbital order-disorder in Nd1-xCaxMnO3 has been studied by high temperature (300 - 1200K) synchrotron and laboratory X-ray powder diffraction in the low doping region…
Motivated by recent interest in quasi-one-dimensional compound CaV2O4, we study the ground states of a spin-orbital chain characterized by an Ising-like orbital Hamiltonian and frustrated interactions between S=1 spins. The on-site…
We have analyzed different correlation functions in a realistic spin-orbital model for half-doped manganites. Using a finite-temperature diagonalization technique the CE phase was found in the charge-ordered phase in the case of small…
We discuss how orbital degeneracy, which is usually removed by a cooperative Jahn-Teller distortion, could under appropriate circumstances lead rather to a Resonating Valence Bond spin-orbital liquid. The key points are: i) The tendency to…
We explore orbital dynamics in the spin liquid candidate Ba3CuSb2O9 using multi-frequency electron spin resonance. We prepared two high quality single crystals. The crystal with a slight copper deficiency shows a structural phase transition…
On basis of analysis of experimental results for more than 200 compounds with 3d and 4f elements we conjecture that atoms with unfilled 3d and 4f shells preserve much of their atomic properties, manifested by the discrete electronic…
With electron filling $n=1$ in the $\rm Sr_2VO_4$ compound, the octahedrally coordinated $t_{\rm 2g}$ orbitals are strongly active due to tetragonal distortion induced crystal field tuning by external agent such as pressure. Considering the…
The ground-state properties of the spin-1 antiferromagnetic Heisenberg model on the corner-sharing tetrahedra, pyrochlore lattice, is investigated. By breaking up each spin into a pair of 1/2-spins, the problem is reduced to the equivalent…
Transition metal compounds with the $(t_{2g})^4$ electronic configuration are expected to be nonmagnetic atomic singlets both in the weakly interacting regime due to spin-orbit coupling, as well as in the Coulomb dominated regime with…
Triangular symmetric molecules with mirror symmetry perpendicular to the 3-fold axis are forbidden to have a fixed electrical dipole moment. However, if the ground state is orbitally degenerate and lacks inversion symmetry, then a…