Related papers: Vertical loop nodes in iron-based superconductors
In multi-band metals quasi-particles arising from different atomic orbitals coexist at a common Fermi surface. Superconductivity in these materials may appear due to interactions within a band (intra-band) or among the distinct metallic…
Motivated by recent experimental investigations of the isovalent doping iron-based superconductors LaFe(AsxP1-x)O1-yFy and NdFe(AsxP1-x)O1-yFy we theoretically study the correlation between the local lattice structure, the Fermi surface,…
We uncover the low-energy spectrum of a t-J model for electrons on a square lattice of spin-1 iron atoms with 3dxz and 3dyz orbital character by applying Schwinger-boson-slave-fermion mean-field theory and by exact diagonalization of one…
The $1D$ phase diagram of a model for correlated hopping of electrons in a lattice of Berry phase molecules is presented. Electrons hop in presence of an extra orbital degree of freedom at each site. This is mimicked as a spin-1 variable…
We have performed high-resolution angle-resolved photoemission spectroscopy on Fe-based superconductor LiFeAs (Tc = 18 K). We reveal multiple nodeless superconducting (SC) gaps with 2D/kBTc ratios varying from 2.8 to 6.4, depending on the…
The recent discovery of superconductivity in iron-arsenic compounds below a transition temperature (Tc) as high as 55K ended the monopoly of copper oxides (cuprates) in the family of high-Tc superconductors. A critical issue in…
A simple interlayer pair tunneling is solved exactly. We find that in the normal state spin-1/2 particle and hole excitations are gapped. But the state is an unusual metal, characterized by novel fermionic spin zero and charge +2e and -2e…
An outstanding problem in the field of high-transition-temperature (high Tc) superconductivity is the identification of the normal state out of which superconductivity emerges in the mysterious underdoped regime. The normal state…
Nodal loop appears when two bands, typically one electron-like and one hole-like, are crossing each other linearly along a one-dimensional manifold in the reciprocal space. Here we propose a new type of nodal loop which emerges from…
We demonstrate that strong inter-orbital interaction is very efficient to achieve superconductivity due to magnetic fluctuations in the iron pnictides. Fermi surface states that are coupled by the antiferromagnetic wave vector are often of…
We analyze the interplay between the absence or presence of the nodes in the superconducting gap along electron Fermi surfaces (FSs) in Fe-pnictides, and 2Delta/T_c along hole FSs, measured by ARPES. We solve the set of coupled gap…
Iron pnictides are the only known family of unconventional high-temperature superconductors besides cuprates. Until recently, it was widely accepted that superconductivity is spin-fluctuation driven and intimately related to their…
Bulk FeSe is a special iron-based material in which superconductivity emerges inside a well-developed nematic phase. We present a microscopic model for this nematic superconducting state, which takes into account the mixing between $s-$wave…
Recent experiments have shown that the phase diagrams of the kagome superconductors $A\mathrm{V}_3\mathrm{Sb}_5$ are strongly impacted by changes in the $c$-axis lattice parameter. Here, we show that $c$-axis deformations impact primarily…
The particular shape of the Fermi surface can give rise to a number of collective quantum phenomena in solids, such as density wave orderings or even superconductivity. In many new iron superconductors this shape, the 'nested' Fermi…
The proximity effect refers to the phenomenon whereby superconducting properties are induced in a normal conductor that is in contact with an intrinsically superconducting material. In particular, the combination of nano-structured…
We find new mechanism of superconductivity beyond the spin-fluctuation theory, the standard model for unconventional superconductivity in the weak coupling approach, where Kondo fluctuations result in multi-gap superconductivity around an…
The superconducting gap is a pivotal character for a superconductor. While the cuprates and conventional phonon-mediated superconductors are characterized by distinct d-wave and s-wave pairing symmetry with nodal and nodeless gap…
While the superconducting transition temperature of hole-doped Ba_{1-x}K_{x}Fe_{2}As_{2} decreases past optimal doping, superconductivity does not completely disappear even for the fully doped KFe_{2}As_{2} compound. In fact,…
Noncentrosymmetric superconductors with various types of pairing interactions are systematically examined with particular focus on phenomena that originate from the differences between Fermi surfaces split by a strong spin-orbit coupling.…