Related papers: Forward Electron-Phonon Scattering in Normal and S…
The complex coupling between charge carriers and phonons is responsible for diverse phenomena in condensed matter. We apply ultrafast electron diffuse scattering to unravel electron-phonon coupling phenomena in 1T-TiSe$_2$ in both momentum…
Fundamental upper bounds on the electron-phonon interaction strength and superconducting transition temperature $T_c$ in metals are established based on the intrinsic instability of the equilibrium between electrons and the crystal lattice…
A softening of phonon-dispersion has been observed experimentally in under-doped cuprate superconductors at the charge-density wave (CDW) ordering wave vector. Interestingly, the softening occurs below the superconducting (SC) transition…
The pseudogap is one of the most pervasive phenomena of high temperature superconductors. It is attributed either to incoherent Cooper pairing setting in above the superconducting transition temperature Tc, or to a hidden order parameter…
We argue that the shape of the dispersion along the nodal and antinodal directions in the cuprates can be understood as a consequence of the interaction of the electrons with collective spin excitations. In the normal state, the dispersion…
For the BCS theory of superconductivity, the electron-phonon interaction is transformed to an attractive electron-electron interaction in the vicinity of the Fermi energy only. At the same time, its formal derivation using a unitary…
A strong electron-phonon interaction arises from the modulation of the superexchange interaction by phonons. As is studied in Phys. Rev. B 70, 184514 (2004), Cu-O bond stretching modes can be soft around (pm pi/a, 0) and (0, pm pi/a), with…
A non-equilibrium Green's function method is applied to model high-field quantum transport and electron-phonon resonances in semiconductor superlattices. The field-dependent density of states for elastic (impurity) scattering is found…
Weak impurity scattering produces a narrow band with a finite density of states near the phase difference $\phi =\pi$ in the mid-gap energy spectrum of a macroscopic superconducting weak link. The equivalent distribution of transmission…
Results for pseudogaps are obtained from a band model, where the stability of the gap depends on the amplitudes of vibrational displacements, or magnetic moments, and their coupling to electrons. A one-particle gap is favored by normal…
Electron-phonon (e-ph) interactions are usually treated in the lowest order of perturbation theory. Here we derive next-to-leading order e-ph interactions, and compute from first principles the associated two-phonon e-ph scattering rates.…
In the correlated electron system with the pseudogap, there are full-gapped domains and Fermi-arced domains coexisting. Those domains are created by the quantum-fluctuated antiferromagnetic fluctuations that generate the short-ranged…
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$_2$…
A comparative study of thermal properties of SmFeAsO, SmFeAs(O0.93F0.07) and SmFeAs(O0.85F0.15) samples is presented. Specific heat and thermal conductivity show clear evidences of the spin density wave (SDW) ordering below TSDW 135 K in…
We explore the role of phase fluctuations in a 3-dimensional s-wave superconductor, NbN, as we approach the critical disorder for the destruction of the superconducting state. Scanning tunneling spectroscopy measurements reveal that in the…
We report an inelastic x-ray scattering investigation of phonons in FeSe superconductor. Comparing the experimental phonon dispersion with density functional theory (DFT) calculations in the non-magnetic state, we found a significant…
Previous experimental studies of the thermal conductivity of plastically deformed lead crystals in the superconducting state have shown strong anomalies in the thermal conductivity. Similar effects were also found for the thermal…
We report the first-principles study of superconducting critical temperature and superconducting properties of Fe-based superconductors taking into account on the same footing phonon, charge and spin-fluctuation mediated Cooper pairing. We…
Superconducting transition temperature $T_C$ of some of the cubic $\beta$-phase Mo$_{1-x}$Re$_x$ alloys with x > 0.10 is an order of magnitude higher than that in the elements Mo and Re. We investigate this rather enigmatic issue of the…
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…