相关论文: Theory of Neutron Scattering for Gapless Neutral S…
Using the standard tight binding model of 2d graphite with short range electron repulsion, we find a gapless spin-1, neutral collective mode branch {\em below the particle-hole continuum} with energy vanishing linearly with momenta at the…
In an earlier work we predicted the existence of a neutral triplet collective mode in undoped graphene and graphite [Phys. Rev. Lett. {\bf 89} (2002) 16402]. In this work we study a phenomenological Hamiltonian describing the interaction of…
Single crystals of the lightly-doped spin-Peierls system Cu(1-x)Cd(x)GeO3 have been studied using bulk susceptibility, x-ray diffraction, and inelastic neutron scattering techniques. We investigate the triplet gap in the magnetic excitation…
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…
In this research has been studied the possibility of existence the neutral triplet collective mode in undoped graphene and graphite without one-cone approximation. This work tries to study this collective mode from different points of view.…
An inelastic neutron scattering study was performed on a Zn-substituted spin-1/2 Heisenberg 2-leg ladder compound Sr(Cu1-xZnx)2O3 (x < 0.04) to investigate nonmagnetic impurity effects on the quantum spin system with a large spin gap of…
We investigate the neutron scattering spectrum in iron pnictides based on the random-phase approximation in the five-orbital model with a realistic superconducting (SC) gap, Delta=5meV. In the normal state, the neutron spectrum is…
Highly oriented pyrolytic graphite (HOPG) has been widely used as monochromators, analyzers and filters at neutron and X-ray scattering facilities. In this Letter we report the first observation of an anomalous neutron Halo scattering of…
We calculate the spin susceptibility at and below T_c for a d_{x^2-y^2}-wave superconductor with resonant impurity scattering and Coulomb correlations. Both the impurity scattering and the Coulomb correlations act to maintain peaks in the…
A universal numerical method is developed for the investigation of magnetic neutron scattering. By applying the pseudospectral-time-domain (PSTD) algorithm to the spinor version of the Schr\"odinger equation, the evolution of the spin-state…
We study collective excitations in a superfluid neutron gas at zero temperature within the quasiparticle random phase approximation. The particle-hole residual interaction is obtained from a Skyrme functional, while a separable interaction…
We report the results of neutron scattering on a powder sample of Gd3Ga5O12 at high magnetic fields. We find that in high fields (B>1.8 T) the system is not fully polarized, but has a small canting of the moments induced by the dipolar…
Quite a few low-dimensional magnets are quantum-disordered ``spin liquids'' with a characteristic gap in the magnetic excitation spectrum. Among these are antiferromagnetic chains of integer quantum spins. Their generic feature are…
Recent polarized neutron scattering experiments on $YBa_2 Cu_3 O_7$ have revealed a sharp spectral peak at the $(\pi,\pi)$ in reciprocal lattice centered around the energy transfer of $41\ meV$. We offer a theoretical explanation of this…
We report a neutron scattering study of the spin-1/2 alternating bond antiferromagnet Cu(NO_3)_2. 2.5D_2O for 0.06<k_BT/J_1<1.5. For k_BT/J_1 << 1 the excitation spectrum is dominated by a coherent singlet-triplet mode centered at…
Recent neutron scattering experiments have revealed that the generic form of the magnetic excitations in the high-Tc cuprates of wide range of doping has the so-called "hourglass" shape; it features both upward and downward excitations at…
Magnetically mediated Cooper pairing is generally regarded as a key to establish the unified mechanism of unconventional superconductivity. One crucial evidence is the neutron spin resonance arising in the superconducting state, which is…
Neutron scattering is a powerful probe of strongly correlated systems. It can directly detect common phenomena such as magnetic order, and can be used to determine the coupling between magnetic moments through measurements of the spin-wave…
We investigate collective spin excitations of graphene electrons with short-ranged interactions and subject to the external Zeeman magnetic field. We find that in addition to the familiar Silin spin wave, a collective spin-flip excitation…
We show how the appearance of d-wave pairing in fermionic condensates manifests itself in inelastic light scattering. Specifically, we calculate the Bragg scattering intensity from the dynamic structure factor and the spin susceptibility,…