相关论文: Detecting sign-changing superconducting gap in LiF…
We report the ultra-fast optical response of quasi-particles (QPs) in both the pseudogap (PG) and superconducting (SC) states of underdoped (UD) Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ (Bi2212) single crystal measured with the…
Amongst the iron-based superconductors, LiFeAs is unrivalled in the simplicity of its crystal structure and phase diagram. However, our understanding of this canonical compound suffers from conflict between mutually incompatible…
We present an Angle-Resolved PhotoElectron Spectroscopy study of the changes in the electronic structure of electron doped Ba(Fe(1-x)Co(x))2As2 across the superconducting phase transition. By changing the polarization of the incoming light,…
We report fully momentum dependent, self-consistent calculations of the gap symmetry, Fermi surface (FS) anisotropy and Tc of superconducting (SC) LiFeAs using the experimental band structure and a realistic small-q electron phonon…
Recently, high resolution angle-resolved photoemission spectroscopy has been used to determine the detailed momentum dependence of the superconducting gap in the high temperature superconductor Bi-2212. In this paper, we first describe…
Detecting quasiparticle tunneling events in superconducting circuits provides information about the population and dynamics of non-equilibrium quasiparticles. Such events can be detected by monitoring changes in the frequency of an…
We report on infrared studies of charge dynamics in a prototypical pnictide system: the BaFe2As2 family. Our experiments have identified hallmarks of the pseudogap state in the BaFe2As2 system that mirror the spectroscopic manifestations of…
The thermal conductivity k of the iron-arsenide superconductor LiFeAs (Tc ~ 18K) was measured in single crystals at temperatures down to T~50mK and in magnetic fields up to H=17T, very close to the upper critical field Hc2~18T. For both…
A simple model of cuprate superconductivity with an electron spectrum prepared by doping is developed. The pair-transfer interaction couples the itinerant band with two components ("hot'' and "cold'') of the defect subsystem. There are…
Defects in LiFeAs are studied by scanning tunneling microscopy (STM) and spectroscopy (STS). Topographic images of the five predominant defects allow the identification of their position within the lattice. The most commonly observed defect…
In the iron-based superconductors (FeSCs), orbital differentiation is an important phenomenon, whereby correlations stronger on the dxy orbital than on the dxz/yz orbital yield quasi-particles with dxy} orbital character having larger mass…
There is an enormous interest in renormalization of quasi-particle (qp) dispersion relation of cuprate superconductors both below and above the critical temperature $T_c$ because it enables determination of the fluctuation spectrum to which…
We discuss the role of electronic correlations in the iron-based superconductor LiFeAs by studying the effects on band structure, mass enhancements, and Fermi surface in the framework of density functional theory combined with dynamical…
High-resolution angle-resolved photoemission experiments reveal subtle modifications of the surface electronic structure of VSe2. Most remarkably, we show that superconductivity can be induced in VSe2 by the right selection of substrate and…
Ultrafast time-resolved optical spectroscopy in high-temperature superconductors enables the direct real-time measurement of non-equilibrium quasiparticle recombination dynamics. In addition, it also gives detailed information about the…
The symmetry and structure of the superconducting gap in the Fe-based superconductors are the central issue for understanding these novel materials. So far the experimental data and theoretical models have been highly controversial. Some…
We present a microscopic theory of transport through quantum dot set-ups coupled to superconducting leads. We derive a master equation for the reduced density matrix to lowest order in the tunneling Hamiltonian and focus on quasiparticle…
Quasiparticle interference (QPI) imaging is well established to study the low-energy electronic structure in strongly correlated electron materials with unrivalled energy resolution. Yet, being a surface-sensitive technique, the…
We investigate theoretically the superconducting state of the undoped Fe-based superconductor ThFeAsN. Using input from $ab~initio$ calculations, we solve the Fermi-surface based, multichannel Eliashberg equations for Cooper-pair formation…
When holes move in the background of strong antiferromagnetic correlation, two effects with different spatial scale emerge, leading to a much reduced hopping integral with an additional phase factor. An effective Hamiltonian is then…