相关论文: Magnetic softness in iron-based superconductors

We show that electron correlations lead to a bad metallic state in chalcogenides FeSe and FeTe despite the intermediate value of the Hubbard repulsion $U$ and Hund's rule coupling $J$. The evolution of the quasi particle weight $Z$ as a…

The effect of isoelectronic substitutions on the microscopic properties of LaFe1-xRuxAsO, for 0< x< 0.8, has been investigated by means of muSR and 139La NMR. It was found that Ru substitution causes a progressive reduction of the N\`eel…

Neutron scattering has played a significant role in characterizing magnetic and structural correlations in Fe$_{1+y}$Te$_{1-x}$Se$_x$ and their connections with superconductivity. Here we review several key aspects of the physics of iron…

We report long-range ordered antiferromagnetism concomitant with local iron displacements in the spin-ladder compound BaFe$_2$Se$_3$. Short-range magnetic correlations, present at room temperature, develop into long-range antiferromagnetic…

Using a slave boson representation of multi-band Hubbard models, we investigate a two-band model relevant to layered perovskites in the vicinity of half-filling. Beside the strong influence of the Hund's rule coupling, we obtain that the…

Effective field theory of magnetic and resistive properties of manganites with account of strong Hund exchange coupling and electron-phonon interactions has been evolved under the strong Hund coupling condition. In parallel with Lang-Firsov…

We study the thermodynamic properties of a small superconducting metallic grain using a quantum Monte Carlo method. The grain is described by the universal Hamiltonian, containing pairing and ferromagnetic exchange correlations. In…

The thickness dependence of spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers is studied using the first-principles non-equilibrium Green's function formalism combined with the Anderson disorder model. A systematic…

We study a four band model for iron-based superconductors within local density approximation + dynamical mean field theory (LDA+DMFT). This successfully reproduces the results of models which take As p degrees of freedom explicitly into…

The correlated motion of electrons in the presence of strong orbital fluctuations and correlations is investigated with respect to magnetic couplings and excitations in an orbitally degenerate ferromagnet. Introduction of the orbital degree…

It is assumed that U atoms in $UGe_2$ have a number of $f$ electrons appropriate to give them each a spin $s=1$ as well as one extra itinerant electron which may equally well be on one or other U atom. The dynamical degrees of freedom are…

The field-angular dependence and anisotropy of the critical current density in iron-based superconductors is evaluated using a phenomenological approach featuring distinct anisotropy factors for the penetration depth and the coherence…

We study tight-binding models of itinerant electrons in two different bands, with effective on-site interactions expressing Coulomb repulsion and Hund's rule. We prove that, for sufficiently large on-site exchange anisotropy, all ground…

We investigate the structural conditions for metamagnetism in MnP and related materials using Density Functional Theory. A magnetic stability plot is constructed taking into account the two shortest Mn-Mn distances. We find that a…

The magnetic field dependence of electron effective mass is an important subject in consideration of physical properties of superconducting ferromagnets URhGe, UCoGe and paramagnet UTe$_2$. It is usually accepted to find this dependence…

The mechanism of Cooper pair formation in iron-based superconductors remains a controversial topic. The main question is whether spin or orbital fluctuations are responsible for the pairing mechanism. To solve this problem, a crucial clue…

The consequences of coupling magnetic and elastic degrees of freedom, where spins and deformations are carried by point-like objects subject to local interactions, are studied, theoretically and by detailed numerical simulations. From the…

For a newly discovered iron-based high T_c superconducting parent material KFe2Se2, we present an effective three-dimensional five-orbital tight-binding model by fitting the band structures. The three t2g-symmetry orbitals of the five Fe 3d…

Since the discovery of high-temperature superconductivity in the thin-film FeSe/SrTiO$_3$ system, iron selenide and its derivates have been intensively scrutinized. Using ab initio density functional theory calculations we review the…

Both DC and AC magnetization measurements were performed on the NdFeAsO0.88F0.12 superconductor to investigate the influence of magnetism on the superconducting properties of this system. The crossover of the ZFC and FC magnetic…