Related papers: Spin waves in La_2CuO_4: band structure and correl…
Charge and spin density distributions are studied within a nano-ring structure endowed with Rashba and Dresselhaus spin orbit coupling (SOI). For a small number of interacting electrons, in the presence of an external magnetic field, the…
We study the ground state properties of an ABA-stacked trilayer graphene. The low energy band structure can be described by a combination of both a linear and a quadratic particle-hole symmetric dispersions, reminiscent of monolayer- and…
Sr_2CuO_3 and Ca_2CuO_3 are considered to be model systems of strongly anisotropic, spin-1/2 Heisenberg antiferromagnets. We report on the basis of a band-structure analysis within the local density approximation and on the basis of…
We construct the 1/S spin-wave expansion for double exchange ferromagnets at T=0. It is assumed that the value of Hund's rule coupling, J_H, is sufficiently large, resulting in a fully saturated, ferromagnetic half-metallic ground state. We…
We study spin fluctuations in quarter-filled one-dimensional spin-density-wave systems in presence of short-range Coulomb interactions. By applying a path integral method, the spin-wave velocity is calculated as a function of on-site (U),…
The field dependence of the electron spin resonance in a helimagnet, LiCu_2O_2, was investigated for the first time. In the paramagnetic state a broad resonance line was observed corresponding to a g-factor of 2.3. In the critical regime…
The usual starting point for understanding magnons in cuprate antiferromagnets such as La$_2$CuO$_4$ is a spin model incorporating cyclic exchange, which descends from a one-band Hubbard model, and has parameters taken from fits based on…
Doping and strain dependences of the electronic structure of the CuO6-octahedra layer within LDA+GTB method in the frameworks of six-band p-d model are calculated. Band structure and Fermi surface of the quasiparticle excitations in the…
We derive an effective Hamiltonian for spin dynamics of fluctuating smectic stripes from the t-J model in the weak coupling limit t >> J. Besides the modulation of spin magnitude, the high energy hopping term would induce a low-energy…
The low energy magnetic excitation spectrum of the Heisenberg antiferromagnetic $S = 1/2$ chain system Sr$_2$CuO$_3$ with Ni- and Ca-impurities is studied by neutron spectroscopy. In all cases, a defect-induced spectral pseudogap is…
Spin and hole excitation spectra and spectral weights are calculated for the half-filled Hubbard model, as a function of $t/U$. We find that the high energy spin spectra are sensitive to charge fluctuations. The energy difference…
We present the results of first-principles cluster calculations of the electronic structure of La_2CuO_4. Several clusters containing up to nine copper atoms embedded in a background potential were investigated. Spin-polarized calculations…
We investigate low-energy properties of two-dimensional quantum spin systems with the ladder and plaquette structures, which are described by a generalized antiferromagnetic Heisenberg model with both of the bond and spin alternations. By…
We report on high-field electron spin resonance (ESR) studies of magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs$_2$CuBr$_4$. Frequency-field diagrams of ESR excitations are measured for different orientations of…
Correlation effects play an important role in the electronic structure of half-metallic (HM) magnets. In particular, they give rise to non-quasiparticle states above (or below) the Fermi energy at finite temperatures that reduce the spin…
The ground state properties and neutron structure factor for the two-dimensional antiferromagnet on the triangular lattice, with uni-directional anisotropy in the nearest-neighbor exchange couplings and a weak Dzyaloshinskii-Moriya (DM)…
Neutron scattering has been used to study the structure and spin dynamics of La$_{0.85}$Sr$_{0.15}$MnO$_3$. The magnetic structure of this system is ferromagnetic below T_C = 235 K. We see anomalies in the Bragg peak intensities and new…
Purely local experimental probes of many copper oxide superconductors show that their electronic states are inhomogeneous in real space. For example, scanning tunneling spectroscopic (STS) imaging shows strong variations in real space, and…
We use the dynamical vertex approximation (D$\Gamma$A) with a Moriyaesque $% \lambda$ correction for studying the impact of antiferromagnetic fluctuations on the spectral function of the Hubbard model in two and three dimensions. Our…
Long-wavelength spin waves in disordered magnetic systems have been investigated. In the framework of the Heisenberg model with magnetic dipole and exchange interactions between spins it is found that an additional longitudinal spin wave…