Related papers: Weak spin interactions in Mott insulating La2O2Fe2…
We report the results of a study of magnetic field features of electron transport in heterojunctions with NS boundary inside iron-based superconductors, represented by a binary phase of $\alpha$ - FeSe and oxyarsenide pnictide LaO(F)FeAs.…
We report neutron scattering measurements of cooperative spin excitations in antiferromagnetically ordered BaFe2As2, the parent phase of an iron pnictide superconductor. The data extend up to ~100meV and show that the spin excitation…
Superconductivity in the iron pnictides and chalcogenides is closely connected to a bad-metal normal state and a nearby antiferromagnetic order. Therefore, considerable attention has been focused on the role of electron correlations and…
We report a study of the Mott insulator La$_2$O$_3$Fe$_2$Se$_2$ by means of $^{139}$La nuclear quadrupole resonance (NQR). The NQR spectra evidence a single La site in the paramagnetic phase and two inequivalent La sites, La1 and La2, in…
We perform a combined experimental-theoretical study of the Fe-oxychalcogenides (FeO$\emph{Ch}$) series La$_{2}$O$_{2}$Fe$_{2}$O\emph{M}$_{2}$ (\emph{M}=S, Se), which is the latest among the Fe-based materials with the potential \ to show…
Discovery of new transition metal compounds with large spin orbit coupling (SOC) coexisting with strong electron-electron correlation among the $d$ electrons is essential for understanding the physics that emerges from the interplay of…
Among the complex many-body systems, the metal-insulator transition stands out as a cornerstone and a particularly fertile ground for scientific inquiry. The established models including Mott insulator, Anderson localization and Peierls…
A new layered iron-oxychalcogenide Na2Fe2OSe2 has been synthesized and structurally characterized by powder X-ray diffraction. The structure is formed by alternate stacking of the newly discovered [Fe2OSe2] blocks and double layers of Na.…
The discovery of superconductivity in the 122 iron selenide materials above 30 K necessitates an understanding of the underlying magnetic interactions. We present a combined experimental and theoretical investigation of magnetic and…
Many recent studies show that superconductivity not only exists in atomically thin monolayers but can exhibit enhanced properties such as higher transition temperature and stronger critical field. Nevertheless, besides being air unstable,…
The spin-orbit Mott insulator Sr3Ir2O7 provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high pressure electric resistance and…
Using thermodynamic measurements and density-functional band-structure calculations, we explore magnetic behavior of SrCuTe2O6. Despite being a structural sibling of a three-dimensional frustrated system PbCuTe2O6, this spin-1/2 quantum…
Fe3-xGeTe2 is an itinerant ferromagnet composed of two-dimensional layers weakly connected by van der Waals bonding that shows a variety of intriguing phenomena. Inelastic neutron scattering measurements on bulk single crystals of…
The temperature dependence of the low-energy magnetic excitations in the spin-triplet superconductor UTe$_2$ was measured via inelastic neutron scattering in the normal and superconducting states. The imaginary part of the dynamic…
We present a comprehensive study of the spin excitations - as measured by the dynamical spin structure factor $S(q,\omega)$ - of the so-called block-magnetic state of low-dimensional orbital-selective Mott insulators. We realize this state…
Sr2IrO4 exhibits a novel insulating state driven by spin-orbit interactions. We report two novel phenomena, namely a large magnetoresistivity in Sr2IrO4 that is extremely sensitive to the orientation of magnetic field but exhibits no…
Protected by the interplay of on-site Coulomb interactions and spin-orbit coupling, Sr$_2$IrO$_4$ at high pressure is a rare example of a Mott insulator with a paramagnetic ground state. Here, using optical Raman scattering, we measure both…
M\"ossbauer spectroscopy was used to probe the site specific information of the $K_{0.84}Fe_{1.99}Se_2$ superconductor. Possibility of coexistence of superconductivity and magnetism is discussed. A spin excitation gap, $\Delta E…
Spin-orbit entangled magnetic dipoles, often referred to as pseudospins, provide a new avenue to explore novel magnetism inconceivable in the weak spin-orbit coupling limit, but the nature of their low-energy interactions remains to be…
Understanding the overall features of magnetic excitation is essential for clarifying the mechanism of Cooper pair formation in iron-based superconductors. In particular, clarifying the relationship between magnetism and superconductivity…