Related papers: Is solid copper oxalate a spin chain or a mixture …
The compounds A$_2$Cu$_3$O(SO$_4$)$_3$ (A=Na, K) are characterized by copper hexamers which are weakly coupled to realize antiferromagnetic order below TN=3 K. They constitute novel quantum spin systems with S=1 triplet ground-states. We…
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…
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…
The electronic and magnetic structure, including the Heisenberg model exchange interaction parameters, was explored for the recently proposed novel cuprate Cu$_2$F$_5$. Using the DFT+U calculation, it is shown that the compound is formed by…
Many proposed and realized spintronic devices involve spin injection and accumulation at an interface between a ferromagnet and a non-magnetic material. We examine the electric field, voltage profile, charge distribution, spin fluxes, and…
We investigate numerically the time dependence of the multiple quantum coherences and entanglement in linear chains up to nine nuclear spins of 1/2 coupled by the dipole-dipole interactions. Two models are considered: (1) a spin chain with…
When two quantum systems are coupled via a mediator, their dynamics has traces of non-classical properties of the mediator. We show how this observation can be effectively utilised to study the quantum nature of materials without…
A system exhibiting multiple simultaneously broken symmetries offers the opportunity to influence physical phenomena such as tunneling currents by means of external control parameters. Time-reversal symmetry and inversion symmetry are both…
Within the fermion-spin theory, the physical properties of the electron pairing state in the copper oxide materials are discussed. According to the common form of the electron Cooper pair, it is shown that there is a coexistence of the…
Correlation is a fundamental statistical measure of order in interacting quantum systems. In solids, electron correlations govern a diverse array of material classes and phenomena such as heavy fermion compounds, Hunds metals, high-Tc…
Low-dimensional copper oxide lattices naturally manifest electronic states with strong short range quantum entanglement, which are known to lead to remarkable emergent material properties. However the nanometer scale many-body wavefunction…
A ferrimagnetic spin model composed of $S=1/2$ spin-dimers and $S=5/2$ spin-chains is studied by combining the bond-operator representation (for $S=1/2$ spin-dimers) and Holstein-Primakoff transformation (for $S=5/2$ spins). A finite…
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…
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…
Several realistic spin-orbital models for transition metal oxides go beyond the classical expectations and could be understood only by employing the quantum entanglement. Experiments on these materials confirm that spin-orbital entanglement…
By means of electron spin resonance investigations we revealed the crucial role of the interchain coupling in the spin dynamics of the spin-1/2 Heisenberg antiferromagnetic (AF) chain material copper-pyrazine-dinitrate,…
We investigate the microscopic origin of the ferromagnetic and antiferromagnetic spin exchange couplings in the quasi one-dimensional cobalt compound Ca3Co2O6. In particular, we establish a local model which stabilizes a ferromagnetic…
Density functional calculations are performed to study the magnetic order of the severely distorted square planar cupric oxide (CuO) and local spin disorder in it in the presence of the transition metal impurities M (= Cr, Mn, Fe, Co and…
We demonstrate that the magnetic susceptibility of strongly alternating antiferromagnetic spin-1/2 chains is an entanglement witness. Specifically, magnetic susceptibility of copper nitrate (CN) measured in 1963 (Berger et al., Phys. Rev.…
Nuclear spins of noble gases can maintain coherence for hours at ambient conditions owing to their extraordinary isolation by the enclosing, complete electronic shells. This isolation, however, impedes the ability to manipulate and control…