Related papers: Spin-Coupling Topology in the Copper Hexamer Compo…
The compounds A2Cu3O(SO4)3 (A=Na,K) are characterized by copper hexamers which are weakly coupled along the b-axis to realize one-dimensional antiferromagnetic chains below TN=3 K, whereas the interchain interactions along the a- and c-axes…
The minerals A2Cu3O(SO4)3 (A2=Na2, NaK, K2) constitute quantum spin systems with copper hexamers as basic structural units. Strong intra-hexamer spin couplings give rise to an effective triplet ground-state. Weak inter-hexamer spin…
Macroscopic assemblies of interacting spins give rise to a broad spectrum of behaviors determined by the spatial arrangement of the magnetic sites and the electronic interactions between them. Compounds of copper (II), in which each copper…
La$_4$Cu$_3$MoO$_{12}$ is a cluster antiferromagnet where copper spin-1/2 form a network of st rongly coupled spin-trimers. The magnetic properties of this material have bee n examined using magnetic neutron scattering. At low temperatures,…
In this paper we demonstrate the application of high magnetic fields to study the magnetic properties of low dimensional spin systems. We present a case study on the series of 2-leg spin-ladder compounds…
Inelastic neutron scattering experiments were performed for the spin-trimer compounds Ca3Cu3-xNix(PO4)4 (x=0,1,2) in order to study the dynamic magnetic properties. The observed excitations can be associated with transitions between the…
The crystal and magnetic structures of the spin $S$=1 hexamer cluster fedotovite-like A$_{2}$Cu$_{3}$O(SO$_4$)$_3$ (A$_2$=K$_2$, NaK, Na$_2$) were studied by neutron powder diffraction at temperatures 1.6-290 K. The crystal structures in…
The $S=1/2$ antiferromagnetic Heisenberg chain is a paradigmatic quantum system hosting exotic excitations such as spinons and solitons, and forming random singlet state in the presence of quenched disorder. Realizing and distinguishing…
Magnetic properties and underlying magnetic models of the synthetic A$_2$Cu$_3$O(SO$_4)_3$ fedotovite (A = K) and puninite (A = Na) minerals, as well as the mixed euchlorine-type NaKCu$_3$O(SO$_4)_3$ are reported. We show that all these…
We review recent theoretical developments about the role of spins, electron-electron interactions, and spin-orbit coupling in metal nanoparticles and semiconductor quantum dots. For a closed system, in the absence of spin-orbit coupling or…
We have investigated the spin dynamics in the strongly correlated chain copper oxide SrCuO$_2$ for energies up to $\gtrsim 0.6$ eV using inelastic neutron scattering. We observe an acoustic band of magnetic excitations which is well…
We report NMR study on the spin correlations in the spin-cluster based mineral Na$_2$Cu$_3$O(SO$_4$)$_3$ with magnetic fields ranged from 1 T to 33 T. The long-range magnetic order is observed from both the sudden spectral broadening at…
The mineral malachite, Cu2(OD)2CO3, has a quantum spin-liquid ground state and no long-range magnetic order down to at least T=0.4 K. Inelastic neutron scattering measurements show that the excitation spectrum consists of dispersive gapped…
With octahedrally coordinated $t_{\rm 2g}$ orbitals which are active at filling $n=2$, the $\rm Sr_2CrO_4$ compound exhibits rich interplay of spin-orbital physics with tetragonal distortion induced crystal field tuning by external agent…
Combining symmetry based considerations with inputs from available experimental results, we make the case that a novel spin-triplet superconductivity triggered by antiferromagnetic fluctuations may be realized in the newly discovered…
In the quest for materials hosting Kitaev spin liquids, much of the efforts have been focused on the fourth- and fifth-row transition metal compounds, which are spin-orbit coupling assisted Mott insulators. Here, we study the structural and…
One of the major themes in correlated electron physics over the last quarter century has been the problem of high-temperature superconductivity in hole-doped copper-oxide compounds. Fundamental to this problem is the competition between…
The quantum spin fluctuations of the S = 1/2 Cu ions are important in determining the physical properties of the high-transition temperature (high-Tc) copper oxide superconductors, but their possible role in the electron pairing for…
In this study, we examine the thermodynamics and spin dynamics of spin-1/2 and spin-3/2 heptamers. Through an exact diagonalization of the isotropic Heisenberg Hamiltonian, we find the closed-form, analytical representations for…
Many physical properties of the copper oxide high temperature superconductors appear to defy the conventional (one-electron) theory of metals, and the development of new theories incorporating strong electron correlations is currently at…