Related papers: Novel Insulating Magnetism in Vacancy-Ordered K2Fe…
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 analyzed the magnetic interactions of a five orbital model for iron superconductors treated both within Hartree-Fock and Heisenberg approximations. We have found that the exchange constants depend non-trivially on the Fe-As-Fe angle…
Single crystal neutron diffraction study has been performed on new superconductor A2Fe4Se5, where A = Cs, K, (Tl,Rb) and (Tl,K), and the same Fe vacancy ordered crystal structure and the same block checkerboard antiferromagne tic order…
We investigate the re-entrant tetragonal phase in the iron-based superconductor Ba0 .76K0.24Fe2As2 by DC magnetization and thermoelectrical measurements. The reversible magnetization confirms by a thermodynamic method that the spin…
Iron chalcogenides display a rich variety of electronic orders in their phase diagram. A particularly enigmatic case is FeTe, a metal which possesses co-existing hole and electron Fermi surfaces as in the iron pnictides but has a distinct…
I present the results of first principles calculations of the electronic structure and magnetic interactions for the recently discovered superconductor YFe$_2$Ge$_2$ and use them to identify the nature of superconductivity and quantum…
Combining in-depth neutron diffraction and systematic bulk studies, we discover that the $\sqrt{5}\times\sqrt{5}$ Fe vacancy order with its associated block antiferromagnetic order is the ground state, with varying occupancy ratio of the…
We study the phase diagram of a square lattice Hubbard model with a perfect vacancy superstructure. The model can be also defined on a new bipartite lattice with each building blocks consisting of a minimal square. The non-interacting model…
We use angle resolved photoemission spectroscopy (ARPES) to study the band structure of BaFe2As2 and CaFe2As2, two of the parent compounds of the iron arsenic high temperature superconductors. We find clear evidence for band back folding…
Topological insulator is composed of an insulating bulk state and time reversal symmetry protected two-dimensional surface states. One of the characteristics of the surface states is the locking between electron momentum and spin…
The varying metallic antiferromagnetic correlations observed in iron-based superconductors are unified in a model consisting of both itinerant electrons and localized spins. The decisive factor is found to be the sensitive competition…
The heavy fermion superconductor CeCoIn5 is believed to be close to a magnetic instability, but no static magnetic order has been found. Cadmium doping on the In-site shifts the balance between superconductivity and antiferromagnetism to…
The recently discovered K-Fe-Se high temperature superconductor has caused heated debate regarding the nature of its parent compound. Transport, angle-resolved photoemission spectroscopy, and STM measurements have suggested that its parent…
We report neutron scattering experiment results revealing the nature of the magnetic order occurring in the heavy fermion superconductor Ce0.95Nd0.05CoIn5, a case for which an antiferromagnetic state is stabilized at a temperature below the…
The electronic structural properties in the presence of constrained magnetization and a charged background are studied for a monolayer of FeSe in non-magnetic, checkerboard-, and striped-antiferromagnetic (AFM) spin configurations. First…
The recent observation of superconductivity in the vicinity of Fermi surface reconstructed insulating or metallic states has established twisted bilayers of WSe\textsubscript{2} as an exciting platform to study the interplay of strong…
High resolution angle-resolved photoemission measurements have been carried out on BaFe2As2, a parent compound of the FeAs-based superconductors. In the magnetic ordering state, there is no gap opening observed on the Fermi surface.…
It is a long-standing important issue in heavy fermion physics whether $f$-electrons are itinerant or localized when the magnetic order occurs. Here we report the {\it in situ} scanning tunneling microscopy observation of the electronic…
Based on an effective 12-orbital tight-binding model, we examine the superconducting states induced by the antiferromagnetic fluctuations for iron-vacancy-ordered A$_{y}$Fe$_{2-x}$Se$_{2}$. It is shown that due to the broken reflection…
The weak antiferromagnetism of URu${}_{2}$Si${}_{2}$ is discussed on the basis of a duality model which takes into account salient features of both itinerant fermions and "localized" component of spin degrees of freedom. The problem is…