Related papers: Frustration-driven C4 symmetric orders in a hetero…
Epitaxial engineering of solid-state heterointerfaces is a leading avenue to realizing enhanced or novel electronic states of matter. As a recent example, bulk FeSe is an unconventional superconductor with a modest transition temperature…
We have performed an angle-resolved photoemission spectroscopy study of a new iron-based superconductor Sr4V2O6Fe2As2. While V 3d orbitals are found to be in a Mott insulator state and show an incoherent peak at ~ 1 eV below the Fermi…
FeSe is employed as reference material to elucidate the observed high Tc superconducting behaviour of the related layered iron pnictides. The structural and ensuing semimetallic band structural forms are here rather unusual, with the…
I review works on Fe-based superconductors which depart from a metal with well defined Fermi surfaces and Fermi liquid-type quasiparticles. I consider normal state instabilities -- SDW magnetism and nematic order, and superconductivity, all…
The iron-based high-$T_c$ superconductors exhibit rich phase diagrams with intertwined phases, including magnetism, nematicity and superconductivity. The superconducting $T_c$ in many of these materials is maximized in the regime of strong…
We report an 75As-NMR study on iron (Fe)-based superconductors with thick perovskitetype blocking layers Sr4(Mg0.5-xTi0.5+x)2O6Fe2As2 with x=0 and 0.2. We have found that antiferromagnetic (AFM) order takes place when x=0, and…
A detailed account of the local atomic structure and disorder at 5~K across the phase diagram of the high temperature superconductor K$_x$Fe$_{2-y}$Se$_{2-z}$S$_z$ $(0 \leq z \leq 2)$ is obtained from neutron total scattering and associated…
Nematicity and magnetism are two key features in Fe-based superconductors, and their interplay is one of the most important unsolved problems. In FeSe, the magnetic order is absent below the structural transition temperature $T_{str}=90$K,…
The iron arsenide Sr2CrO3FeAs with the tetragonal Sr2GaO3CuS-type structure was synthesized and its crystal structure re-determined by neutron powder diffraction. In contrast to previous X-ray crystallographic studies, a mixed occupancy of…
The interplay between superconductivity and ferromagnetism has long been pursued as a route to unconventional Josephson effects, yet suitable material platforms remain limited. Here we report Josephson junctions based on epitaxial…
FeTe is a prototypical parent compound of iron-based superconductors. While bulk FeTe is non-superconducting with a long-range bicollinear antiferromagnetic order, superconductivity has been achieved in thin films. However, the approaches…
We calculate electronic structures of a high-Tc iron-based superconductor Sr2VFeAsO3 by LDA+U method. We assume a checker-board antiferromagnetic order on blocking layers including vanadium and strong correlation in d-orbits of vanadium…
Superconductivity at 33 K in Sr2VO3FeAs is completely suppressed by small amounts of V-doping in Sr2VO3[Fe0.93(+/-0.01)V0.07(+/-0.01)]As. The crystal structures and exact stoichiometries are determined by combined neutron- and x-ray powder…
An SDW antiferromagnetic (SDW-AF) low temperature phase transition is generally observe and the AF spin fluctuations are considered to play an important role for the superconductivity paring mechanism in FeAs superconductors. However, a…
High-temperature superconductivity occurs near antiferromagnetic instabilities and nematic state. Debate remains on the origin of nematic order in FeSe and its relation with superconductivity. Here, we use transport, neutron scatter- ing…
Superconductivity is significantly enhanced in monolayer FeSe grown on SrTiO3, but not for multilayer films, in which large strength of nematicity develops. However, the link between the high-transition temperature superconductivity in…
Bulk magnetization, transport and neutron scattering measurements were performed to investigate the electronic and magnetic properties of a polycrystalline sample of the newly discovered ferromagnetic superconductor,…
The electronic structure of the enigmatic iron-based superconductor FeSe has puzzled researchers since spectroscopic probes failed to observe the expected electron pocket at the $Y$ point in the 1-Fe Brillouin zone. It has been speculated…
We report muon spin rotation ($\mu$SR) and magnetization measurements on superconducting Sr$_{2}$VO$_{3}$FeAs under pressure. At ambient pressure, Sr$_{2}$VO$_{3}$FeAs undergoes an antiferromagnetic transition of the V moments at $T_{N}$…
Superconductivity in strongly correlated electron systems frequently emerges in proximity to another broken symmetry. In heavy-electron superconductors, the nearby ordered state most commonly is magnetism, and the so-called Ce115…