Related papers: One-Dimensional Confinement and Enhanced Jahn-Tell…
The local and intermediate structure of stoichiometric LaMnO$_3$ has been studied in the pseudocubic and rhombohedral phases at high temperatures (300 to 1150 K). Neutron powder diffraction data were collected and a combined Rietveld and…
One- and multi-phonon excitations of the single crystalline LaCoO3 were studied using Raman spectroscopy in the temperature region of 5 K - 300 K. First-order Raman spectra show a larger number of phonon modes than allowed for the…
The first-principles SIC-LSD theory is utilized to study electronic, magnetic and orbital phenomena in LaMnO$_{3}$. The correct ground state is found, which is antiferro orbitally ordered with the spin magnetic moments antiferromagnetically…
We present a revised atomistic picture of the order-disorder transition in the archetypal orbital-ordered perovskite material, LaMnO$_{3}$. Our study uses machine-learning-driven molecular-dynamics simulations which describe the temperature…
We study the ground state orbital ordering of $LaMnO_3$, at weak electron-phonon coupling, when the spin state is A-type antiferromagnet. We determine the orbital ordering by extending to our Jahn-Teller system a recently developed Peierls…
A neutron scattering study of the Mott-Hubbard insulator LaTiO$_{3}$ (T$_{{\rm N}}=132$ K) reveals a spin wave spectrum that is well described by a nearest-neighbor superexchange constant $J=15.5$ meV and a small Dzyaloshinskii-Moriya…
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…
The effect of uniaxial strain on electronic structure and magnetism in LaMnO$_3$ is studied from a model Hamiltonian that illustrates the competition between the Jahn-Teller, super exchange, and double exchange interactions. We retain in…
We report a thorough study of Y$_{0.7}$La$_{0.3}$VO$_3$ single crystals by measuring magnetic properties, specific heat, thermal conductivity, x-ray and neutron diffraction with the motivation of revealing the lattice response to the…
The Jahn-Teller effect in the charge-ordered (CO) state for La1-xCaxMnO3 (0.5<x<0.87) was studied by measuring the low-temperature powder x-ray diffraction, internal friction, and shear modulus. We find that the electron-lattice interaction…
We study the interplay of spin, orbital and lattice degrees of freedom in a one-dimensional Kugel-Khomskii model coupled to phonons. In the vicinity of the dimer point we analyze the excitation spectrum, mapping the spin and orbital degrees…
Fractionalization of an electronic quasiparticle into spin, charge and orbital parts is a fundamental and characteristic property of interacting electrons in one dimension. However, real materials are never strictly one-dimensional and the…
Interplay of spin-orbit coupling and vibronic coupling on heavy $d^1$ site of cubic double perovskites is investigated by ab initio calculations. The stabilization energy of spin-orbital-lattice entangled states is found comparable to or…
Roles of orbital and lattice degrees of freedom in strongly correlated systems are investigated to understand electronic properties of perovskite Mn oxides such as La_{1-x}Sr_{x}MnO_{3}. An extended double-exchange model containing Coulomb…
We present a linear spin and orbital wave theory to account for the spin and orbital orderings observed experimentally in undoped manganite. It is found that the anisotropy of the magnetic structure is closely related to the orbital…
Dynamical Jahn-Teller (DJT) effect in a spin-orbital coupled system on a honeycomb lattice is examined, motivated from recently observed spin-liquid behavior in Ba$_3$CuSb$_2$O$_9$. An effective vibronic Hamiltonian, where the superexchange…
The ground state of a double-exchange model for orbitally degenerate $e_g$ electrons with Jahn-Teller lattice coupling and weak disorder is found to be spatially inhomogeneous near half filling. Using a real space Monte-Carlo method we show…
We have studied the volume collapse of LaMnO$_3$ at the Jahn- Teller (JT) transition temperature T$_{JT}$=750 K which has recently been found in high temperature powder x- ray and neutron diffraction experiments. We construct a model…
We have studied the interplay between orbital ordering, Jahn-Teller and GdFeO3-type lattice distortions in perovskite-type transition-metal oxides using model Hartree-Fock calculations. It has been found that the covalency between A-site…
We report on combined neutron and resonant x-ray scattering results, identifying the nature of the spin-orbital ground state and magnetic excitations in LuVO3 as driven by the orbital parameter. In particular, we distinguish between models…