Related papers: Unconventional superconductivity originating from …
The discovery of high-transition temperature (high-Tc) superconductivity near antiferromagnetism in iron arsenides raised the possibility of an unconventional superconducting mechansim1-8. The observation of clear Fermi surfaces and…
Superconductivity above 25K, and possibly above 40K, has recently been discovered in $LaO_{1-x}F_xFeAs$ and related compounds. We propose that this is another example of the mechanism of hole superconductivity at play. This requires the…
We report extensive measurements of quantum oscillations in the normal state of the Fe-based superconductor LaFePO, (Tc ~ 6 K) using low temperature torque magnetometry and transport in high static magnetic fields (45 T). We find that 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…
Unconventional superconductivity is commonly linked to electronic pairing mechanisms, since it is believed that the conventional electron-phonon interaction (EPI) cannot cause sign-changing superconducting gap symmetries. Here, we show that…
In the iron-based superconductors, understanding the relation between superconductivity and electronic structure upon doping is crucial for exploring the pairing mechanism. Recently it was found that in iron selenide (FeSe), enhanced…
The phase diagram of LaFeAs$_{1-x}$P$_x$O system has been extensively studied through hole- and electron-doping as well as As/P-substitution. It has been revealed that there are three different superconducting phases with different Fermi…
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…
Since the discovery of superconductivity\cite{1} at 26 K in oxy-pnictide $LaFeAsO_{1-x}F_x$, enormous interests have been stimulated in the fields of condensed matter physics and material sciences. Among the five different structures in…
The electronic and magnetic properties of the new hydride superconductor CaFeAsH, which superconducts up to 47 K when electron-doped with La, and the isovalent alloy system CaFeAsH$_{1-x}$F$_x$ are investigated using density functional…
According to the Bardeen-Cooper-Schrieffer (BCS) theory, superconductivity usually needs well defined Fermi surface(s) with strong electron-phonon coupling and moderate quasiparticle density of states (DOS). A kagome lattice can host flat…
Here, we present a de Haas-van Alphen (dHvA) effect1 study on the newly discovered LaFeAsO1-xFx compounds2,3 in order to unveil the topography of the Fermi surface associated with their antiferromagnetic and superconducting phases, which is…
The layered iron superconductors are discussed using electronic structure calculations. The four families of compounds discovered so far, including Fe(Se,Te) have closely related electronic structures. The Fermi surface consists of…
Obtaining the electronic structure of the newly discovered iron-based superconductors is the key to understanding the mechanism of their high-temperature superconductivity. We used angle-resolved photoemission spectroscopy (ARPES) to make…
Electrons on Kagome lattice exhibit a wealth of features including Dirac points, van Hove singularities and flatbands. When the Fermi level is placed at the van Hove saddle point, the Fermi surface is perfectly nested and a rich variety of…
We use angle-resolved photoemission spectroscopy (ARPES) to investigate the electronic properties of the newly discovered oxypnictide superconductor, NdFeAsO_{1-x}F_x. We find a well-defined Fermi surface that consists of a large hole…
In unconventional superconductors, it is generally believed that understanding the physical properties of the normal state is a pre-requisite for understanding the superconductivity mechanism. In conventional superconductors like niobium or…
We present a theoretical study of the dynamical spin susceptibility for the intriguing Fe-based superconductor FeSe, based on a tight-binding model developed to account for the temperature-dependent band structure in this system. The model…
The nature and value of the order parameters (OPs) in the superconducting Fe-based oxypnictides REFeAsO_(1-x)F_x (RE = rare earth) are a matter of intense debate, also connected to the pairing mechanism which is probably unconventional.…
Two families of high temperature superconductors whose critical temperatures are higher than 50K are known. One is the copper oxides and the other is the iron-based superconductors. Comparisons of mechanisms between these two in terms of…