Related papers: Two-orbital degeneracy lifted state as a local pre…
The local structure of NaTiSi$_{2}$O$_{6}$ is examined across its Ti-dimerization orbital-assisted Peierls transition at 210 K. An atomic pair distribution function approach evidences local symmetry breaking preexisting far above the…
A novel Ti3+-based thiospinel ZnTi2S4 is successfully synthesized via a low-temperature ion-exchange reaction. ZnTi2S4 shows a signature of metallic ground state evidenced by a contribution of conduction electrons in the heat capacity and…
The transition metal spinel MgTi$_2$O$_4$ undergoes a metal-insulator transition on cooling below $T_{M-I} = 260$ K. A sharp reduction of the magnetic susceptibility below $T_{M-I}$ suggests the onset of a magnetic singlet state. Using…
We summarize some characteristic features of the frustrated magnetic interactions in spin-orbital models adequate for cubic transition metal oxides with orbital degeneracy. A generic tendency towards dimerization, found already in the…
Layered 5d transition metal oxides (TMOs) have attracted significant interest in recent years because of the rich physical properties induced by the interplay between spin-orbit coupling, bandwidth and on-site Coulomb repulsion. In Sr2IrO4,…
Using density-functional theory calculations and experimental investigations on structural, magnetic and dielectric properties, we have elucidated a unique tetragonal ground state for MnTi2O4, a Ti^{3+} (3d^1)-ion containing spinel-oxide.…
The lifting of degenerate electronic states, in which multiple electronic states share the same energy, is a fundamental issue in the physics of crystalline solids. In real materials, this problem has been extensively studied in transition…
LiV_2 O_4 is one of the most puzzling compounds among transition metal oxides because of its heavy fermion like behavior at low temperatures. In this paper we present results for the orbital state and magnetic properties of LiV_2 O_4…
Low-temperature heat-capacity investigations on the spinel FeCr2S4 with ferrimagnetic spin order and orbitally degenerated Jahn-Teller active Fe2+ ions in a tetrahedral crystal field, provide experimental evidence of an orbital liquid state…
The first-order metal-insulator transition (MIT) in paramagnetic $V_{2}O_{3}$ is studied within the ab-initio scheme LDA+DMFT, which merges the local density approximation (LDA) with dynamical mean field theory (DMFT). With a fixed value of…
The ferrimagnetic spinel $\mathrm{CoV_2O_4}$ has been a topic of intense recent interest, both as a frustrated insulator with unquenched orbital degeneracy and as a near-itinerant magnet which can be driven metallic with moderate applied…
We consider the superstructures, which can be formed in spinels containing on B-sites the transition-metal ions with partially filled t2g levels. We show that, when such systems are close to itinerant state (e.g. have an insulator-metal…
Transition metal oxides exhibit various competing phases and exotic phenomena depending on how their reaction to the rich degeneracy of the $d$-orbital. Large spin-orbit coupling (SOC) reduces this degeneracy in a unique way by providing a…
Dimension reduction due to the orbital ordering has recently been proposed to explain the exotic charge, magnetic and structural transitions in some three-dimensional (3D) transitional metal oxides. We present optical measurement on a…
We report on neutron diffraction, thermal expansion, magnetostriction, dielectric, and specific heat measurements on polycrystalline FeCr2S4 in external magnetic fields. The ferrimagnetic ordering temperatures $T_{\mathrm{C}}\approx 170$ K…
Sr2IrO4 exhibits a novel insulating state assisted by spin-orbit interactions. A series of polycrystalline samples of Sr2-xIrO4 have been synthesized. It is found that deep Sr-vacancies of Sr2-xIrO4 greatly reduce the rotation of IrO6…
CuAl2O4 is a normal spinel oxide having quantum spin, S=1/2 for Cu2+. It is a rather unique feature that the Cu2+ ions of CuAl2O4 sit at a tetrahedral position, not like the usual octahedral position for many oxides. At low temperatures, it…
We address the concomitant metal-insulator transition (MIT) and antiferromagnetic ordering in the novel pyrochlore iridate Eu2Ir2O7 by combining x-ray absorption spectroscopy, x-ray and neutron diffractions and density functional theory…
Tetragonal distorted spinel of CuMn2-xTixO4 (x = 0, 0.25 and 0.50) was prepared by solid state reaction method followed by neutron diffraction, FTIR spectroscopy, dielectric spectroscopy and magnetization measurements. The neutron…
By applying dynamical mean-field theory in combination with exact diagonalization at zero temperature to a half-filled Hubbard model with two orbitals having distinct noninteracting densities of states, we show that an orbital selective…