Related papers: (Sr_3Sc_2O_5)Fe_2As_2 as a possible parent compoun…

An unusual successive phase transition from superconducting (SC) to antiferromagnetic (AF) phases was discovered via ^{75}As and ^{27}Al nuclear magnetic resonance (NMR) in (Fe_2As_2)(Ca_6(Al, Ti)_4O_y) with four (Al, Ti)O layers…

We report a novel superconducting (SC) and antiferromagnetic (AF) hybrid state in SrFe2As2 revealed by 75As nuclear magnetic resonance (NMR) experiments on a single crystal under highly hydrostatic pressure up to 7 GPa. The NMR spectra at…

We have performed an extensive ab initio LDA and LSDA+U calculations of electronic structure of newly discovered high-temperature superconducting series ReO(1-x)F(x)FeAs (Re=La,Ce, Pr, Nd, Sm and hypothetical case of Re=Y). In all cases we…

By means of first-principle FLAPW-GGA calculations, we have investigated the electronic properties of the newly discovered layered quaternary systems SrFeAsF and CaFeAsF as parent phases for a new group of oxygen-free FeAs superconductors.…

This paper reports that ~10-nm-thick FeSe thin films exhibit insulator-like behavior in terms of the temperature dependence of their electrical resistivity even though bulk FeSe has a metallic electronic structure that has been confirmed by…

The electronic structure and physical properties of the pnictide compound families $RE$OFeAs ($RE$ = La, Ce, Pr, Nd, Sm), $A$Fe$_{2}$As$_{2}$ ($A$ = Ca, Sr, Ba, Eu), LiFeAs and FeSe are quite similar. Here, we focus on the members of the…

We present the results of paramagnetic LDA band structure calculations: band dispersions, densities of states and Fermi surfaces, for the new iron based high-temperature superconductor LiOHFeSe. Main structural motif providing bands in the…

Two-dimensional iron-chalcogenide intercalates display a remarkable correlation of the interlayer spacing with the enhancement of the superconducting critical temperature ($T_c$). In this work, synchrotron x-ray absorption ($XAS$, at Fe and…

The record of superconducting transition temperature(Tc) has long been 56K for the iron-based high temperature superconductors(Fe-HTS's). Recently, in single layer FeSe films grown on SrTiO3 substrate, signs for a new 65K Tc record are…

Parent compounds AFe2As2 (A=Ca, Ba, Eu) of the 122 family of the iron-based superconductors have been studied by 57Fe Moessbauer spectroscopy in the temperature range 4.2 K - ~300 K. Spin density waves (SDW) have been found with some…

We report resistivity measurement under pressure in single crystals of SrFe_2As_2, which is one of the parent materials of Fe-based superconductors. The structural and antiferromagnetic (AFM) transition of T_0 = 198 K at ambient pressure is…

In addition to higher Tc compared with the ubiquitous cuprates for a material composed of a single electronically active layer, the newly discovered LnFeAsO superconductors offer additional compositional variation. In a similar fashion to…

We report that intrinsic transport and magnetic properties, and their anisotropy from high quality single crystal $CaFe_2As_2$. The resistivity anisotropy ($\rho_c/\rho_{ab}$) is $\sim 50 $, and less than 150 of $BaFe_2As_2$, which arises…

We have successfully synthesized a new layered iron oxychalcogenide BaFe2OSe2 single crystal. This compound is built up of Ba and Fe-Se(O) layers alternatively stacked along the c-axis. The Fe-Se(O) layers contain double chains of…

Coupling among conduction electrons (e.g. Zhang-Rice singlet) are often manifested in the core level spectra of exotic materials such as cuprate superconductors, manganites, etc. These states are believed to play key roles in the ground…

One of the most popular scenarios for the superconductivity in Fe-based superconductors (FeBSC) posits that the bosons responsible for electronic pairing are spin-fluctuations with a wave vector spanning the hole Fermi surfaces (FSs) near…

The chromium arsenides BaCr2As2 and BaCrFeAs2 with ThCr2Si2 type structure (space group I4/mmm; also adopted by '122' iron arsenide superconductors) have been suggested as mother compounds for possible new superconductors. DFT-based…

Iron-based superconductors Ba0.7Rb0.3Fe2As2 and CaFe1.92Co0.08As2 of the '122' family have been investigated by means of the 14.41-keV Moessbauer transition in 57Fe versus temperature ranging from the room temperature till 4.2 K. A…

One of the unifying concepts in the iron-pnictide superconductors, both for the mechanism of magnetic ordering and of unconventional order parameter character, has been the electron and hole Fermi surfaces that are approximately nested.…

The low-temperature antiferromagnetic state of the Sm-ions in both nonsuperconducting SmFeAsO and superconducting SmFeAsO$_{0.9}$F$_{0.1}$ single crystals was studied by magnetic torque, magnetization, and magnetoresistance measurements in…