Related papers: Spin-wave excitations in the SDW state of doped ir…
Spin waves in (0,pi) and (0,pi,pi) ordered spin-density-wave (SDW) states of the t-t' Hubbard model are investigated at finite doping. In the presence of small t', these composite ferro-antiferromagnetic (F-AF) states are found to be…
The doping dependence of spin excitations in Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ is studied based on a two-orbital model under RPA approximation. The interplay between the spin-density-wave (SDW) and superconductivity (SC) is considered in…
We investigate the role of Hund's coupling in the spin-wave excitations of the ($\pi, 0$) ordered magnetic state within a five-orbital tight-binding model for iron pnictides. To differentiate between the roles of intraorbital Coulomb…
We present a general study of the magnetic excitations within a weak-coupling five-orbital model relevant to itinerant iron pnictides. As a function of enhanced electronic correlations, the spin excitations in the symmetry broken…
Aimed at identifying the role of microscopic Hamiltonian parameters on spin wave excitations, orbital order, and magnetic moments in the $(\pi,0)$ SDW state, two different three band models for iron pnictides are compared --- one at…
We study theoretically the coexistence of the spin-density-wave (SDW) and superconductivity in electron-doped iron-pnictide superconductors based on the two orbital model and Bogoliubov-de Gennes equations. The phase diagram is mapped out…
We use polarized inelastic neutron scattering to study the temperature and energy dependence of spin space anisotropies in the optimally hole-doped iron pnictide Ba$_{0.67}$K$_{0.33}$Fe$_{2}$As$_{2}$ ($T_{{\rm c}}=38$ K). In the…
Doping dependence of the spin fluctuations and the electron correlations in the effective five-band Hubbard model for iron pnictides is investigated using the fluctuation-exchange approximation. For a moderate hole doping, we find a…
Motivated by the iron pnictides, we examine the spin excitations in an itinerant antiferromagnet where a spin-density wave (SDW) originates from an excitonic instability of nested electron-like and hole-like Fermi pockets. Using the random…
Spin wave excitations and stability of the (0,pi) ordered SDW state are investigated within the minimal two-band model for iron pnictides including a Hund's coupling term. The SDW state is shown to be stable in two distinct doping regimes…
Elucidating the nature of spin excitations is important to understanding the mechanism of superconductivity in the iron pnictides. Motivated by recent inelastic neutron scattering measurements in the nearly 100% detwinned…
The proximity of antiferromagnetic order in high-temperature superconducting materials is considered a possible clue to the electronic excitations which form superconducting pairs. Here we study the transverse and longitudinal spin…
Chiral magnetic textures, such as skyrmions, are of great interest to the condensed matter community due to their novel transport properties. The stabilization of topologically non-trivial magnetic phases, like the skyrmion lattice in MnSi,…
Employing the four-band tight-binding model we study theoretically the doping dependence of the spin response in the normal state of novel Fe-based pnictide superconductors. We show that the commensurate spin density wave (SDW) transition…
Using a degenerate double-exchange model, we investigate the spin excitation spectra of iron pnictides. The model consists of local spin moments on each Fe site, as well as itinerant electrons from the degenerate $d_{xz}$ and $d_{yz}$…
We explore the anisotropy in low frequency conductivity as a function of hole doping in multiorbital models of pnictides by analyzing the Drude weight in the $x$ and $y$ directions of a ($\pi$, 0) spin-density wave state. A reduction in the…
The evolution of electronic (spin and charge) excitations upon carrier doping is an extremely important issue in superconducting layered cuprates and the knowledge of its asymmetry between electron- and hole-dopings is still fragmentary.…
We argue that salient experimental features of the magnetic excitations in the SDW phase of iron-based superconductors can be understood within an itinerant model. We identify a minimal itinerant model and use a multi-band RPA treatment of…
We use inelastic neutron scattering (INS) spectroscopy to study the magnetic excitations spectra throughout the Brioullion zone in electron-doped iron pnictide superconductors BaFe$_{2-x}$Ni$_{x}$As$_{2}$ with $x=0.096,0.15,0.18$. While the…
We study the doping dependence of the spin-density-wave (SDW) state in four models of the 1111 pnictides. The random-phase approximation is used to determine the ordering temperature and the ordering vector as functions of doping, and to…