Related papers: Phonon Anomalies Induced by Superconductivity
The Fermi surface of most hole-doped cuprates is close to a Van Hove singularity at the M point. A two-dimensional electronic system, whose Fermi surface is close to a Van Hove singularity shows a variety of weak coupling instabilities. It…
We report density functional calculations of the electronic structure, Fermi surface, phonon spectrum, magnetism and electron-phonon coupling for the superconducting phase FeSe, as well as the related compounds FeS and FeTe. We find that…
Recent experiments suggest that besides of antiferromagnetic fluctuations nematic fluctuations may contribute to the occurrence of superconductivity in iron pnictides. Motivated by this observation we study superconductivity from nematic…
We report numerical results of quantum oscillations of the specific heat in the vortex state of a $d_{x^2-y^2}$-wave superconductor in the presence of loop current order, which gives rise to Fermi pockets coexisting with nodal…
(Li0.8Fe0.2)OHFeSe is a newly-discovered intercalated iron-selenide superconductor with a Tc above 40 K, which is much higher than the Tc of bulk FeSe (8 K). Here we report a systematic study of (Li0.8Fe0.2)OHFeSe by low temperature…
We analyze Cooper pairing instabilities in strongly driven electron-phonon systems. The light-induced non-equilibrium state of phonons results in a simultaneous increase of the superconducting coupling constant and the electron scattering.…
We consider the optical conductivity of a clean two-dimensional metal near a quantum spin-density-wave transition. Critical magnetic fluctuations are known to destroy fermionic coherence at "hot spots" of the Fermi surface but coherent…
We analyze quantum fluctuation effects at the onset of charge or spin density wave order in two-dimensional metals with an incommensurate $2k_F$ wave vector connecting a single pair of hot spots on the Fermi surface. We compute the momentum…
We present an explanation of the unusual peak/dip/hump features observed in photoemission experiments on Bi2212 at $T \ll T_c$. We argue that these features arise from the interaction of the fermionic quasi-particles with overdamped spin…
When a second-order magnetic phase transition is tuned to zero temperature by a non-thermal parameter, quantum fluctuations are critically enhanced, often leading to the emergence of unconventional superconductivity. In these `quantum…
We propose that if there are two small pocket-like Fermi surfaces, and the spin susceptibility is pronounced around a wave vector {\bf Q} that bridges the two pockets, the spin-singlet superconductivity mediated by spin fluctuations may…
We study the superconductivity of strongly coupled electron-phonon systems where the geometry of the lattice frustrates the charge order by the sign-problem-free Quantum Monte Carlo(QMC) method. The results suggest that with charge order…
We argue that the low- frequency quantum oscillations observed recently in the vortex state of underdoped ortho II-YBCO have the same origin as in other strongly correlated electronic systems. Superconductivity driven by strong interactions…
Based on density functional calculations, the relationship between magnetism or superconductivity and electronic states around Fermi level were derived, and the location of the Fermi level in nonmagnetic "form" of Laves-phase compounds is…
In a superconductor with magnetic impurities, Kondo scattering results in the formation of localized states inside the superconducting gap. We show that inelastic electronic transitions involving quasiparticle scattering into and out of the…
We interpret the upper-critical-field anomalies observed in some high- temperature superconductors as resulting from the proximity to a zero-temperature quantum critical point. We estimate the shape of the phase boundary between the normal…
The key feature of the Fe-based superconductors is their quasi 2D multiband Fermi surface. By relating the problem to a negative U Hubbard model and its superconducting ground state, we show that the defining instability of such a Fermi…
A pair-density wave state has been suggested to exist in underdoped cuprate superconductors, with some supporting experimental evidence emerging over the past few years from scanning tunneling spectroscopy. Several studies have also linked…
The volt-ampere curves and their second derivatives were studied for niobium point contacts at low temperatures in the voltage range corresponding to the characteristic phonon energies. It was found that while for the dirty contacts in the…
We performed a high-resolution angle-resolved photoemission spectroscopy study of the Tl$_{0.63}$K$_{0.37}$Fe$_{1.78}$Se$_2$ superconductor ($T_c=29$ K). We show the existence of two electronlike bands at the M$(\pi, 0)$ point which cross…