Related papers: Superconductivity without magnetism in LiFeAs
I describe the issues of the competing orders in normal state of a parent and Ni-doped iron pnictide superconductor, SrF e 2 As 2 , using LMTO band structure calculation plus multi orbital dynamical mean-field theory. Strong, electronic…
According to [M.A. Tanatar et al., Phys. Rev. Lett. 95, 067002 (2005)], in a multi-band d-wave superconductor CeCoIn5 electrons remain partially uncondensed. Interactions must induce superconducting order on all Fermi surfaces. We calculate…
We present a brief review of the present day situation with studies of high-temperature superconductivity in iron pnictides and chalcogenides. Recent discovery of superconductivity with T_c > 30 K in A_xFe_{2-x/2}Se_2 (A=K,Cs,Tl,...)…
We report an angle-resolved photoemission study of BaFe2As2, a parent compound of iron-based superconductors. Low-energy tunable excitation photons have allowed the first observation of a saddle-point singularity at the Z point, as well as…
We have studied the low-lying electronic structure of a new ThCr$_2$Si$_2$-type superconductor KNi$_2$Se$_2$ with angle-resolved photoemission spectroscopy. Three bands intersect the Fermi level, forming complicated Fermi surface topology,…
We have performed high-resolution angle-resolved photoemission spectroscopy of iron-chalcogenide superconductor Fe1.03Te0.7Se0.3 (Tc = 13 K) to investigate the electronic structure relevant to superconductivity. We observed a hole- and an…
We propose that a new state with a fully gapless Fermi surface appears in quasi-2D multiband superconductors in magnetic field applied parallel to the plane. It is characterized by a paramagnetic moment caused by a finite density of states…
One of the central tenets of conventional theories of superconductivity, including most models proposed for the recently discovered iron-pnictide superconductors, is the notion that only electronic excitations with energies comparable to…
We report the first photoemission study of Fe$_{1+x}$Te - the host compound of the newly discovered iron-chalcogenide superconductors (maximum T$_c$ $\sim$ 27K). Our results reveal a pair of nearly electron-hole compensated Fermi pockets,…
Based on the effective four-band model we analyze the spin response in the normal and superconducting states of the Fe-pnictide superconductors. While the normal state spin excitations are dominated by the continuum of the interorbital…
Unconventional superconductivity has recently been discovered in the first iron-based superconducting silicide LaFeSiH. By using the complementary techniques of muon spin rotation, tunneling diode oscillator and density functional theory,…
The electronic structure of electron doped iron-arsenide superconductors Ba(Fe1- xCox)2As2 has been measured with Angle Resolved Photoemission Spectroscopy. The data reveal a marked photon energy dependence of points in momentum space where…
For the iron-based high $T_c$ superconductor LaFeAsO$_{1-x}$F$_x$, we construct a minimal model, where all of the five Fe $d$ bands turn out to be involved. We then investigate the origin of superconductivity with a five-band random-phase…
We measured the Fermi surface of the recently discovered superconductor Ag5Pb2O6 via a de Haas-van Alphen rotation study. Two frequency branches were observed and identified with the neck and belly orbits of a very simple, nearly free…
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…
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…
An unusual quasi-two-dimensional heavy band mass van Hove singularity (vHs) lies very near the Fermi energy in MgCNi3, recently reported to superconduct at 8.5 K. This compound is strongly exchange enhanced and is unstable to ferromagnetism…
The relationship between unconventional superconductivity, antiferromagnetism and nematic order in iron-based superconductors (FeSCs) is still highly debated. In many FeSCs superconductivity is in proximity of a nematically and magnetically…
Besides the conventional spin-density-wave (SDW) state, a new kind of orbital-transverse density-wave (OTDW) state is shown to exist generally in multi-orbital systems. We demonstrate that the orbital character of Fermi surface nesting…
Topological superconductivity is an exotic phase of matter in which the fully gapped superconducting bulk hosts gapless Majorana surface states protected by topology. Intercalation of copper, strontium or niobium between the quintuple…