Related papers: Spin-Orbit Excitons in CoO
Motivated by the presence of an unquenched orbital angular momentum in CoO, a team at Chalk River, including a recently hired research officer Roger Cowley, performed the first inelastic neutron scattering experiments on the classic Mott…
The strongly correlated insulator Ca$_{2}$RuO$_4$ is considered as a paradigmatic realization of both spin-orbital physics and a band-Mott insulating phase, characterized by orbitally selective coexistence of a band and a Mott gap. We…
Multi-band Mott insulators with moderate spin-orbit and Hund's coupling are key reference points for theoretical concept developments of correlated electron systems. The ruthenate Mott insulator Ca$_{2}$RuO$_{4}$ has therefore been…
Using Raman spectroscopy to study the correlated 4$d$-electron metal Sr$_2$RhO$_4$, we observe pronounced excitations at 220 meV and 240 meV with $A_\mathrm{1g}$ and $B_\mathrm{1g}$ symmetries, respectively. We identify them as transitions…
A unified approach is presented for investigating coupled spin-orbital fluctuations within a realistic three-orbital model for strongly spin-orbit coupled systems with electron fillings $n=3,4,5$ in the $t_{2g}$ sector of…
We carried out inelastic neutron scattering to study the spin-orbital (SO) exciton in a single crystal sample of CoTiO$_3$ as a function of temperature. CoTiO$_3$ is a honeycomb magnet with dominant XY-type magnetic interaction and an…
We study the structural, magnetic, transport and electronic properties of LaCoO$_3$ with Sr/Nb co-substitution, i.e., La$_{(1-2x)}$Sr$_{2x}$Co$_{(1-x)}$Nb$_{x}$O$_3$ using x-ray and neutron diffraction, dc and ac-magnetization, neutron…
Neutron scattering is used to investigate the single-ion spin and orbital excitations below the Mott-Hubbard gap in CoO. Three excitations are reported at 0.870 $\pm$ 0.009 eV, 1.84 $\pm$ 0.03, and 2.30 $\pm$ 0.15 eV. These were…
$\gamma$-triclinic and $\alpha$-monoclinic polymorphs of CoV$_{2}$O$_{6}$ are two of the few known transition metal ion based materials that display stepped $1/3$ magnetization plateaus at low temperatures. Neutron diffraction [M. Markkula…
By means of neutron scattering we have determined new branches of magnetic excitations in orbitally active CoO (TN=290 K) up to 15 THz and for temperatures from 6 K to 450 K. Data were taken in the (111) direction in six single-crystal…
Mott insulators based on $4d$ and $5d$ transition-metal ions, where spin-orbit interaction plays a key role, can exhibit various forms of unusual magnetism. A particular example is the antiferromagnet Ca$_2$RuO$_4$ containing $d^4$…
We present the main features of the spin-orbital superexchange which describes the magnetic and optical properties of Mott insulators with orbital degrees of freedom. In contrast to the SU(2) symmetry of spin superexchange, the orbital part…
Study of the combined effects of strong electronic correlations with spin-orbit coupling (SOC) represents a central issue in quantum materials research. Predicting emergent properties represents a huge theoretical problem since the presence…
The double perovskite Ba$_{2}$NaOsO$_{6}$ (BNOO), an exotic example of a very high oxidation state (heptavalent) osmium $d^1$ compound and also uncommon by being a ferromagnetic Mott insulator without Jahn-Teller (JT) distortion, is modeled…
We study the interplay between superconductivity and antiferromagnetic spin fluctuations in electron-doped cobaltate Na$_{x}$CoO$_{2}\cdot y$H$_{2}$O based on the kinetic energy driven superconductivity mechanism. We show that the…
We apply the finite-temperature variational cluster approach to a strongly correlated and spin-orbit coupled model for four electrons (i.e. two holes) in the $t_{2g}$ subshell. We focus on parameters suitable for antiferromagnetic Mott…
We use a local model to study the formation and the structure of the low energy charge transfer excitations in the insulating Cu-O$_2$ plane. The elementary excitation is a bound exciton of spin singlet, consisting of a Cu$^+$ and a…
We have measured the intricate temperature dependence of the Co L2,3 x-ray absorption spectra (2p-3d excitations) of CoO. To allow for accurate total electron yield measurements, the material has been grown in thin film form on a metallic…
The metal-insulator and spin state transitions of CoO under high pressure are studied by using density functional theory combined with dynamical mean-field theory. Our calculations predict that the metal-insulator transition in CoO is a…
The electronic properties of excitonic insulators have been examined precisely in recent years. Pictures of exciton condensation may be applied to the spin-state transition observed in perovskite cobalt oxides. We examine the crystal-field…