相关论文: Superconductivity in Fe and As based compounds: a …

The theory of hole superconductivity explains high temperature superconductivity in cuprates as driven by pairing of hole carriers in oxygen $p\pi$ orbitals in the highly negatively charged $Cu-O$ planes. The pairing mechanism is hole…

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…

The recent discovery of superconductivity with relatively high transition temperature Tc in the layered iron-based quaternary oxypnictides La[ O1-xFx] FeAs was a real surprise. The excitement generated can be seen by the number of…

Inelastic scattering of visible light (Raman effect) offers a window into properties of correlated metals such as spin, electron and lattice dynamics as well as their mutual interactions. In this review we focus on electronic and spin…

We investigated the material parameters of several single-layer cuprates, including those with fluorinated buffer layers, with the aim of identifying possible high-temperature superconductors. To evaluate the material parameters, we use the…

We derive analytic expressions for the critical temperatures of the superconducting (SC) and pseudogap (PG) phases of the high-Tc cuprates, which are in excellent agreement with the experimental data for single-layered materials such as…

We use electronic Raman scattering to study the model single-layer cuprate superconductor HgBa2CuO4+d. In an overdoped sample, we observe a pronounced amplitude enhancement of a high-energy peak related to two-magnon excitations in…

The recent observations of superconductivity at temperatures up to 55K in compounds containing layers of iron arsenide have revealed a new class of high temperature superconductors that show striking similarities to the more familiar…

In Fe-As based superconductors magnetism and superconductivity show strong sensitivity to the lattice, suggesting a possibility of unconventional electron-phonon coupling. We investigated c-axis polarized phonons in doped and undoped…

Understanding the mechanism and symmetry of electron pairing in iron-based superconductors represents an important challenge in condensed matter physics [1-3]. The observation of magnetic flux lines - "vortices" - in a superconductor can…

We express the superconducting gap, $\Delta(T)$, in terms of thermodynamic functions in both $s$- and d-wave symmetries. Applying to Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ and Y$_{0.8}$Ca$_{0.2}$Ba$_2$Cu$_3$O$_{7-\delta}$ we find that for all…

We propose that the contrasting low-temperature behaviors observed experimentally among isostructural and isoelectronic materials, like non-superconducting and nonmagnetic MgFeGe, magnetically ordered NaFeAs, and superconducting LiFeAs, can…

The two-gap model for superconductivity in MgB2 predicts that interband impurity scattering should be pair breaking, reducing the critical temperature. This is perhaps the only prediction of the model that has not been confirmed…

Unveiling the nature of the pseudogap and its relation to both superconductivity and antiferromagnetic Mott insulators, the pairing mechanism, and a non-Fermi liquid phase is a key issue for understanding high temperature superconductivity…

Scanning tunneling microscopy/spectroscopy (STM/STS) measurements were carried out on a multi-layered cuprate superconductor Ba$_2$Ca$_5$Cu$_6$O$_{12}$(O$_{1-x}$,F$_x$)$_2$. STM topography revealed random spot structures with the…

The surprising discovery of tripling the superconducting critical temperature of KFe$_2$As$_2$ at high pressures issued an intriguing question of how the superconductivity in the collapsed tetragonal phase differs from that in the…

Understanding the interplay between superconductivity and the pseudogap phase is essential for elucidating the mechanism of high-temperature superconductivity in cuprates. Here we provide direct spatial evidence that these two states are…

We have synthesized 10 new iron oxyarsenides, K$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Gd, Tb, Dy, and Ho) and Cs$Ln_2$Fe$_4$As$_4$O$_2$ ($Ln$ = Nd, Sm, Gd, Tb, Dy, and Ho), with the aid of lattice-match [between $A$Fe$_2$As$_2$ ($A$ = K and Cs)…

AgF$_2$ is a correlated charge-transfer insulator with properties remarkably similar to insulating cuprates which have raised hope that it may lead to a new family of unconventional superconductors upon doping. We use ab initio computations…

A brief review of optical and Raman studies on the Fe-based superconductors is given, with special emphasis on the competing phenomenon in this system. Optical investigations on ReFeAsO (Re=rare-earth element) and AFe$_2$As$_2$…