相关论文: Suppression of antiferromagnetic spin fluctuations…

A spin-triplet superconducting state mediated by ferromagnetic (FM) spin fluctuations has been suggested to occur in the newly discovered heavy-fermion superconductor UTe$_2$. However, the recent neutron scattering measurements revealed the…

We present high-energy x-ray diffraction data under applied pressures up to p = 29 GPa, neutron diffraction measurements up to p = 1.1 GPa, and electrical resistance measurements up to p = 5.9 GPa, on SrCo2As2. Our x-ray diffraction data…

The influence of hydrostatic pressure and ab-plane strain on the magnetic structure of FeTe is investigated from first principles. The results of calculations reveal a phase transition from antiferromagnetic double-stripe ordering at…

At ambient pressure CaFe2As2 has been found to undergo a first order phase transition from a high temperature, tetragonal phase to a low temperature orthorhombic / antiferromagnetic phase upon cooling through T ~ 170 K. With the application…

Inelastic neutron scattering measurements of paramagnetic SrCo$_{2}$As$_{2}$ at T=5 K reveal antiferromagnetic (AFM) spin fluctuations that are peaked at a wavevector of $\textbf{Q}_{\mathrm{AFM}}=(1/2,1/2,1)$ and possess a large energy…

Characterizing magnetic fluctuations is one of the keys to understanding the origin of superconductivity in the spin-triplet superconductor UTe$_2$ which exhibits two superconducting (SC) phases (SC1 and SC2) under pressure: SC1 where a…

This work presents 75As NMR spin echo decay rate (1/T2) measurements in Ba(Fe1-xRhx)2As2 superconductors, for 0.041 < x < 0.094. It is shown that 1/T2 increases upon cooling, in the normal phase, suggesting the onset of an unconventional…

We use inelastic neutron scattering to study acoustic phonons and spin excitations in single crystals of NaFeAs, a parent compound of iron pnictide superconductors. NaFeAs exhibits a tetragonal-to-orthorhombic structural transition at…

We report $^{75}$As NMR studies on single crystals of rare-earth doped iron pnictides superconductor Ca$_{1-x}$Pr$_{x}$Fe$_{2}$As$_{2}$ ($x$=0.075 and 0.15). The $^{75}$As spectra show a chemical pressure effect with doping and a first…

In the iron pnictides, the strong sensitivity of the iron magnetic moment to the arsenic position suggests a significant relationship between phonons and magnetism. We measured the phonon dispersion of several branches in the high…

CaFe2As2 single crystals under uniaxial pressure applied along the c axis exhibit the coexistence of several structural phases at low temperatures. We show that the room-temperature tetragonal phase is stabilized at low temperatures for…

We use inelastic neutron scattering to study energy and wave vector dependence of spin fluctuations in SrCo$_2$As$_2$, derived from SrFe$_{2-x}$Co$_x$As$_2$ iron pnictide superconductors. Our data reveals the coexistence of…

Structural and electronic characterization of (Ca0.67Sr0.33)Fe2As2 has been performed as a func- tion of pressure up to 12 GPa using conventional and designer diamond anvil cells. The compound (Ca0.67Sr0.33)Fe2As2 behaves intermediate…

We present detailed electronic structure calculations for CaFe2As2. We investigate in particular the `collapsed' tetragonal and orthorhombic regions of the temperature-pressure phase diagram and find properties that distinguish CaFe2As2…

The density functional non-interacting susceptibility has been analyzed in different phases of CaFe2As2 and compared with similar data for pure d-metals. The conditions for the "no local moment" itinerant state with large frustrations are…

Recent observations of selective emergence (suppression) of superconductivity in the uncollapsed (collapsed) tetragonal phase of LaFe$_2$As$_2$ has rekindled interest in understanding what features of the band structure control the…

We review neutron scattering investigations of the crystal structures, magnetic structures, and spin dynamics of the iron-based RFe(As,P)O (R=La, Ce, Pr, Nd), (Ba,Sr,Ca)Fe2As2, and Fe1+x(Te-Se) systems. On cooling from room temperature all…

We have performed powder inelastic neutron scattering measurements on the unconventional superconductor $\beta$-FeSe ($T_{\rm c} \simeq 8\,\mathrm{K}$). The spectra reveal highly dispersive paramagnetic fluctuations emerging from the…

A well-known feature of CaFe$_{2}$As$_{2}$-based superconductors is the pressure-induced collapsed tetragonal phase that is commonly ascribed to the formation of an interlayer As-As bond. Using detailed X-ray scattering and spectroscopy, we…

We report inelastic neutron scattering studies of magnetic excitations in antiferromagnetically ordered SrFe$_{2}$As$_{2}$ ($T_{N}=220$ K), the parent compound of the FeAs-based superconductors. At low temperatures (T=7 K), the spectrum of…