Related papers: Kohn Anomalies in Superconductors
We performed temperature- and doping-dependent high-resolution Raman spectroscopy experiments on YBa$_2$Cu$_3$O$_{7-\delta}$ to study $B$$_{\rm 1g}$ phonons. The temperature dependence of the real part of the phonon self-energy shows a…
Raman studies on Ca4Al2O5.7Fe2As2 superconductor in the temperature range of 5 K to 300 K, covering the superconducting transition temperature Tc ~ 28.3 K, reveal that the Raman mode at ~ 230 cm-1 shows a sharp jump in frequency by ~ 2 %…
The dispersion of electrons and phonons near the K point of bilayer graphene was investigated in a resonant Raman study using different laser excitation energies in the near infrared and visible range. The electronic structure was analyzed…
The effect of ordering field phase fluctuations on the normal and superconducting properties of a simple 2D model with a local four-fermion attraction is studied. Neglecting the coupling between the spin and charge degrees of freedom an…
In this work, a question is tackled concerning the formation of a superconducting condensate in an earlier proposed model of "elastic jelly", in which phonons of the ion system play the part of initiating ones. It was shown that in…
A universal high energy anomaly in the single particle spectral function is reported in three different families of high temperature superconductors by using angle-resolved photoemission spectroscopy. As we follow the dispersing peak of the…
We consider the temperature dependence of the sound attenuation and sound velocity in layered impure metals due to superconducting fluctuations of the order parameter above the critical temperature. We obtain the dependence on material…
We extend the well-established action of the Higgs mode in $s$-wave superconductors to include quantum fluctuations (QFs). We find that already one-loop quantum corrections to the Higgs propagator shift its eigenfrequency below the…
The properties of an unconventional, single mode phonon bath coupled to a quantum dot, are investigated within the rotating wave approximation. The electron current through the dot induces an out of equilibrium bath, with a phonon…
Intensity of the first- and the second-order Raman spectra are calculated as a function of the Fermi energy. We show that the Kohn anomaly effect, i.e., phonon frequency renormalization, in the first-order Raman spectra originates from the…
Unlike classical fluids, a quantum Fermi liquid can support a long-lived and propagating shear sound wave at arbitrarily small wave vectors and frequencies, reminiscent of the transverse sound in crystals, despite lacking any form of…
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…
Oscillations of conductance observed in strong magnetic fields are a striking manifestation of the quantum dynamics of charge carriers in solids. The large charge carrier density in typical metals sets the scale of oscillations in both…
ARPES measurements on underdoped cuprates above the superconducting transition temperature exhibit the unique phenomenon of Fermi arcs, gapless arcs of Fermi surface around the nodal points of the superconducting gap, which terminate before…
We have performed high resolution angle-resolved photoemission measurements on superconducting electron-doped NaFe$_{0.95}$Co$_{0.05}$As ($T_{c}\sim$18 K). We observed a hole-like Fermi surface around the zone center and two electron-like…
We analyze the influence of a local pairing on the quantum interference in nanoscopic systems. As a model system we choose the double quantum dot coupled to one metallic and one superconducting electrode in the T-shape geometry. The…
Gapless superconductivity can arise when pairing occurs between fermion species with different Fermi surface sizes, provided there is a sufficiently large mismatch between Fermi surfaces and/or at sufficiently large coupling constant. In…
The Kondo effect in superconductors is frequently investigated using the local quasiparticle density of states as sole bath characteristics, i.e., the presence of anomalous propagators is ignored. Here we point out that this treatment is…
We present a new method of determining the anisotropy of the gap function in layered high-Tc superconductors. Careful inelastic neutron scattering measurements at low temperature of the phonon dispersion curves in the (100) direction in…
Superconductivity in FeSe has recently attracted a great deal of attention because it emerges out of an electronic nematic state of elusive character. Here we study both the electronic normal state and the superconducting gap structure…