Related papers: Direct observation of the superconducting gap in p…
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…
We estimate the effect of the superconducting gap anisotropy in the dispersive gap mode of phonons, which is observed by the neutron scattering on borocarbide superconductors. We numerically analyze the phonon spectrum considering the…
We calculate superconducting gaps and quasiparticle density of states of YNi$_2$B$_2$C in the framework of the density functional theory for superconductors to investigate the origin of a highly anisotropic superconducting gaps in this…
We present scanning tunneling spectroscopy and microscopy measurements at low temperatures in the borocarbide materials RNi2B2C (R=Y, Lu). The characteristic strong coupling structure due to the pairing interaction is unambiguously resolved…
We present an inelastic neutron scattering study of phonon lineshapes in the vortex state of the type-II superconductor YNi$_2$B$_2$C. In a previous study [Phys. Rev. Lett. \textbf{101}, 237002 (2008)] it was shown that certain phonons…
Point contacts are used to investigate the anisotropy of the superconducting energy gap in LuNi2B2C in the ab plane and along the c axis. It is shown that the experimental curves should be described assuming that the superconducting gap is…
Lortz et al. [Phys. Rev. B 73, 024512 (2006)] have utilized specific heat and resistivity measurements as "thermal spectroscopies" to deconvolve the spectrum of the electron-phonon interaction in YB$_6$ assuming a major role of the low…
We present a study of the anisotropy in the superconducting energy gap in a single crystal of YNi2B2C (Tc~14.6K) using directional point contact spectroscopy. The superconducting energy gap at 2.7K, when measured for I||c, is 4.5 times…
Recent inelastic-neutron-scattering measurements of a low-energy phonon in Bi_2Sr_2CaCu_2O_8 provide enough information to place a lower bound on the energy gap magnitude at precise locations on the Fermi surface. Measurements of a few…
We present a method to determine the nodal structure of the energy gap of unconventional superconductors such as high $T_c$ materials. We show how nonlinear electrodynamics phenomena in the Meissner regime, arising from the presence of…
We report first-principles calculations of the superconducting properties of $\beta$--Bi$_2$Pd within the fully anisotropic Migdal-Eliashberg formalism. We find a single anisotropic superconducting gap of $s$--wave symmetry which varies in…
Point-contact spectroscopy was originally developed for the determination of the electron-phonon spectral function in normal metals. However, in the past 20 years it has become an important tool in the investigation of superconductors. As a…
Recent intensive experimental studies revealed that (Y,Lu)Ni$_2$B$_2$C is an anisotropic s-wave superconductor. In addition, its gap function possesses deep point minima, whose ratio of the gap anisotropy is more than 10. On the theoretical…
We calculate the electronic polarizability in the superconducting state near extremum vectors ${\vec Q}_0$ of the Fermi surface. A pole appears in the polarizability at frequencies $\omega$ near the superconducting gap $2\Delta$ which leads…
We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy to directly observe the large superconducting (SC) gap anisotropy (GA) of YNi2B2C. The result shows large SC GA with a smooth variation along an intersection…
We measured the Fermi surface (FS), band dispersion and superconducting gap in LuNi2B2C using Angle Resolved Photoemission Spectroscopy. Experimental data were compared with the tight-binding version of the Linear Muffin-Tin Orbital (LMTO)…
Pseudogap phase in superconductors continues to be an outstanding puzzle that differentiates unconventional superconductors from the conventional ones (BCS-superconductors). Employing high resolution photoemission spectroscopy on a highly…
The optical properties of YNi$_2$B$_2$C are studied by using the first-principles full-potential linearized augmented plane wave (FLAPW) method within the local density approximation. Anisotropic behavior is obtained in the optical…
The temperature dependence below $T_{c}$ of the lineshape of optical phonons of different symmetry as seen in Raman scattering is investigated for superconductors with anisotropic energy gaps. It is shown that the symmetry of the…
Superconductivity-induced changes of phonon lineshapes in niobium have been re-investigated by high-resolution inelastic neutron scattering. We show that the changes go beyond a simple change in lifetime and frequency when the phonon…