Related papers: Quantum Fluctuations in the van der Walls material…
We study collective spin excitations in two-dimensional diluted magnetic semiconductors, placed into external magnetic field. Two coupled modes of the spin waves (the electron and ion modes) are found to exist in the system along with a…
We report on the dynamics of the spin-1/2 quasi-one-dimensional frustrated magnet LiCuVO$\mathrm{_4}$ measured by nuclear spin relaxation in high magnetic fields 10--34 T, in which the ground state has spin-density-wave order. The spin…
We study a model of interacting fermions in a disordered potential, which is assumed to generate uniformly fluctuating interaction matrix elements. We show that the ground state magnetization is systematically decreased by off-diagonal…
We investigate the spectral shape, the anisotropy of the wave vector distributions and the anisotropy of the amplitudes of the magnetic fluctuations in the Earth's magnetosheath within a broad range of frequencies. We present the first…
The Raman scattering response of the biaxial antiferromagnet CoPS$_3$ has been investigated as a function of both magnetic field and temperature. The peaks observed in the low-frequency spectral range (90--200~cm$^{-1}$) have been…
Van der Waals (vdW) magnets have rapidly emerged as a fertile playground for novel fundamental physics and exciting applications. Despite the impressive developments over the past few years, technical limitations pose a severe challenge to…
Spin fluctuations in superconducting BaFe2(As1-xPx)2 (x=0.34, Tc = 29.5 K) are studied using inelastic neutron scattering. Well-defined commensurate magnetic signals are observed at ({\pi},0), which is consistent with the nesting vector of…
Current magnetic traps can be made so anisotropic that the atomic gas trapped inside behaves like quasi one or two dimensional system. Unlike the homogeneous case, quantum phase fluctuations do not destroy macroscopic off-diagonal order of…
The scenario of a metal-insulator transition driven by the onset of antiferromagnetic order in NaOsO$_3$ calls for a trustworthy derivation of the underlying effective spin Hamiltonian. To determine the latter we rely on {\it ab initio}…
We study the excitation spectrum of the $S=1/2$ Heisenberg model on the randomly diluted square lattice by analytic continuation of QMC data. At dilution fractions $p=1/16$ and $p=1/8$, the dynamic structure factor $S({\bf q},\omega)$…
The spectral function of transverse spin fluctuations, including the contributions from both the single-particle and the collective (magnon) excitations in an antiferromagnet, is evaluated for the Hubbard model with NN and NNN hoppings in…
We construct a set of exact ground states with a localized ferromagnetic domain wall and with an extended spiral structure in a deformed flat-band Hubbard model in arbitrary dimensions. We show the uniqueness of the ground state for the…
Recently it was discovered that van der Waals-bonded magnetic materials retain long range magnetic ordering down to a single layer, opening many avenues in fundamental physics and potential applications of these fascinating materials. One…
We report inelastic neutron scattering measurements of the spin dynamics in the layered hexagonal magnet 2H-AgNiO2 which has stacked triangular layers of antiferromagnetically-coupled Ni2+ spins (S=1) ordered in a collinear alternating…
In two-dimensional (2D) nearly square-lattice quantum materials, electron correlations can induce an electronic nematic phase with twofold rotational ($C_2$) symmetry that profoundly impacts their properties. For 2D materials with threefold…
In this paper quantum effects are investigated in a very special two-scalar field model having a moduli space of BPS topological defects. In a $(1+1)$-dimensional space-time the defects are classically degenerate in mass kinks, but in…
We present the theory for the effects of superconducting pairing fluctuations on the nuclear spin-lattice relaxation rate, 1/T_1, and the NMR Knight shift for layered superconductors in high magnetic fields. These results can be used to…
The emerging magnetic van der Waals (vdW) materials provide a platform for exploring novel physics regarding magnetism in low dimensions and developing ultrathin spintronic applications. Here, we investigate the ultrafast dynamics of…
Sr_2Cu_3O_4Cl_2 is an antiferromagnet consisting of weakly coupled CuO planes which comprise two weakly interacting antiferromagnetic subsystems, I and II, which order at respective temperatures T_I \approx 390K and T_{II} \approx 40K.…
Neutron scattering can provide detailed information about the energy and momentum dependence of the magnetic dynamics of materials provided sufficiently large single crystals are available. This requirement has limited the number of rare…