Related papers: Spin and Charge Dynamics Ruled by Antiferromagneti…
The magnetic excitations of charge-stripe ordered La2NiO4.11 where investigated using polarized- and unpolarized-neutron scattering to determine the magnetic excitations of the charge stripe electrons. We observed a magnetic excitation mode…
Strong resonant enhancements of the charge-order and spin-order superstructure-diffraction intensities in La1.8Sr0.2NiO4 are observed when x-ray energies in the vicinity of the Ni L2,3 absorption edges are used. The pronounced photon-energy…
We used single-crystal x-ray and neutron diffraction to investigate the crystal and magnetic structures of trigonal lattice iridate Ca2Sr2IrO6. The crystal structure is determined to be $R\bar3$ with two distinct Ir sites. The system…
Quantum Monte Carlo and density-matrix renormalization group methods are used to study the coupled spin-pseudospin Hamiltonian in one-dimension (1D) that models the charge-ordering instability of the anisotropic Hubbard ladder at quarter…
We report inelastic neutron scattering experiments on single crystals of superconducting Ba0.67K0.33Fe2As2 (Tc = 38 K). In addition to confirming the resonance previously found in powder samples, we find that spin excitations in the normal…
Elastic neutron scattering is used to study the spin correlations in the multiferroic $\rm Mn_{1-x}Fe_{x}WO_4$ with $x=0.035, 0.05$ and 0.10. The noncollinear, incommensurate (ICM) magnetic structure associated with the ferroelectric (FE)…
Recent nuclear magnetic resonance (NMR) measurements revealed the coexistence of stripe-type antiferromagnetic (AFM) and ferromagnetic (FM) spin correlations in both the hole- and electron-doped BaFe$_2$As$_2$ families of iron-pnictide…
Superconductivity in FeSe emerges from a nematic phase that breaks four-fold rotational symmetry in the iron plane. This phase may arise from orbital ordering, spin fluctuations, or hidden magnetic quadrupolar order. Here we use inelastic…
In this Letter we report high-resolution synchrotron X-ray powder diffraction and transmission electron microscope analysis of Mn-substituted LaFeAsO samples, demonstrating that a static incommensurate modulated structure develops across…
NaFe$_{0.5}$Cu$_{0.5}$As represents a rare exception in the metallic iron pnictide family, in which a small insulating gap is opened. Based on first-principles study, we provide a comprehensive theoretical characterization of this…
Emergent symmetry breakings in condensed matter systems are often intimately linked to collective excitations. For example, the intertwined spin-charge stripe order in cuprate superconductors is associated with spin and charge excitations.…
Recent neutron scattering and transport data obtained on underdoped YBCO, with strong signatures of rotation symmetry breaking at low temperatures, point toward electron-nematic order in the charge sector. Such order may originate from a…
Multiband superconductivity, involving resonant pair scattering between different bands, has emerged as a possible explanation of some of the main characteristics of the recently discovered iron pnictides. A key feature of such interband…
The A-site ordered chromate spinels LiGa1-xInxCr4O8 host a network of size-alternating spin-3/2 Cr3+ tetrahedra known as a 'breathing' pyrochlore lattice. For the x=0.05 composition, the complex magneto-structural ordering observed in the…
We study the spin resonance peak in recently discovered iron-based superconductors. The resonance peak observed in inelastic neutron scattering experiments agrees well with predicted results for the extended $s$-wave ($s_\pm$) gap symmetry.…
Quantum criticality in iron pnictides involves both the nematic and antiferromagnetic degrees of freedom, but the relationship between the two types of fluctuations has yet to be clarified. Here we study this problem in the presence of a…
The spin dynamics of all ferromagnetic materials are governed by two types of collective excitations: spin waves and domain walls. The fundamental processes underlying these collective modes, such as exchange interactions and magnetic…
We use polarized inelastic neutron scattering (INS) to study spin excitations in superconducting NaFe0.985Co0.015As (C15) with static antiferromagnetic (AF) order along the a-axis of the orthorhombic structure and NaFe0.935Co0.045As (C45)…
We have performed inelastic neutron scattering measurements on a powder sample of the superconductor lithium iron selenide hydroxide Li$_{1-x}$Fe$_{x}$ODFe$_{1-y}$Se ($x \simeq 0.16, y \simeq 0.02$, $T_{\rm c} = 41$\,K). The spectrum shows…
Examination of the electrical resistivities of iron pnictides shows that they can be accounted by conduction by polarons. Their activation energies show a linear behaviour with the critical temperatures of the spin density waves (SDW), T*,…