10 research outputs found
Identification of the bulk pairing symmetry in high-temperature superconductors: Evidence for an extended s-wave with eight line nodes
we identify the intrinsic bulk pairing symmetry for both electron and
hole-doped cuprates from the existing bulk- and nearly bulk-sensitive
experimental results such as magnetic penetration depth, Raman scattering,
single-particle tunneling, Andreev reflection, nonlinear Meissner effect,
neutron scattering, thermal conductivity, specific heat, and angle-resolved
photoemission spectroscopy. These experiments consistently show that the
dominant bulk pairing symmetry in hole-doped cuprates is of extended s-wave
with eight line nodes, and of anisotropic s-wave in electron-doped cuprates.
The proposed pairing symmetries do not contradict some surface- and
phase-sensitive experiments which show a predominant d-wave pairing symmetry at
the degraded surfaces. We also quantitatively explain the phase-sensitive
experiments along the c-axis for both Bi_{2}Sr_{2}CaCu_{2}O_{8+y} and
YBa_{2}Cu_{3}O_{7-y}.Comment: 11 pages, 9 figure
Gaussian Tunneling Model of c-Axis Twist Josephson Junctions
We calculate the critical current density for c-axis Josephson
tunneling between identical high temperature superconductors twisted an angle
about the c-axis. We model the tunneling matrix element squared as a
Gaussian in the change of wavevector q parallel to the junction, . The
obtained for the s- and extended-s-wave order parameters (OP's) are consistent
with the BiSrCaCuO data of Li {\it et al.}, but only
for strongly incoherent tunneling, . A -wave OP
is always inconsistent with the data. In addition, we show that the apparent
conventional sum rule violation observed by Basov et al. might be
understandable in terms of incoherent c-axis tunneling, provided that the OP is
not -wave.Comment: 6 pages, 6 figure
Electron Dynamics in NdCeCuO: Evidence for the Pseudogap State and Unconventional c-axis Response
Infrared reflectance measurements were made with light polarized along the a-
and c-axis of both superconducting and antiferromagnetic phases of electron
doped NdCeCuO. The results are compared to
characteristic features of the electromagnetic response in hole doped cuprates.
Within the CuO planes the frequency dependent scattering rate,
1/, is depressed below 650 cm; this behavior is a
hallmark of the pseudogap state. While in several hole doped compounds the
energy scales associated with the pseudogap and superconducting states are
quite close, we are able to show that in NdCeCuO
the two scales differ by more than one order of magnitude. Another feature of
the in-plane charge response is a peak in the real part of the conductivity,
, at 50-110 cm which is in sharp contrast with the
Drude-like response where is centered at . This
latter effect is similar to what is found in disordered hole doped cuprates and
is discussed in the context of carrier localization. Examination of the c-axis
conductivity gives evidence for an anomalously broad frequency range from which
the interlayer superfluid is accumulated. Compelling evidence for the pseudogap
state as well as other characteristics of the charge dynamics in
NdCeCuO signal global similarities of the cuprate
phase diagram with respect to electron and hole doping.Comment: Submitted to PR
Global creepex distribution and its relation to earthquake source geometry and tectonic origin
Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
Study of local interactions between earthquakes in Pannonian basin
Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal