13 research outputs found
Effects of Electron-Electron and Electron-Phonon Interactions in Weakly Disordered Conductors and Heterostuctures
We investigate quantum corrections to the conductivity due to the
interference of electron-electron (electron-phonon) scattering and elastic
electron scattering in weakly disordered conductors. The electron-electron
interaction results in a negative -correction in a 3D conductor. In
a quasi-two-dimensional conductor, ( is the thickness, is
the Fermi velocity), with 3D electron spectrum this correction is linear in
temperature and differs from that for 2D electrons (G. Zala et. al., Phys.
Rev.B {\bf 64}, 214204 (2001)) by a numerical factor. In a
quasi-one-dimensional conductor, temperature-dependent correction is
proportional to . The electron interaction via exchange of virtual phonons
also gives -correction. The contribution of thermal phonons interacting
with electrons via the screened deformation potential results in -term and
via unscreened deformation potential results in -term. The interference
contributions dominate over pure electron-phonon scattering in a wide
temperature range, which extends with increasing disorder.Comment: 6 pages, 2figure
Quantum interference of electrons in Nb_{5-\delta}Te_4 single crystals
The compound () with quasi-one-dimensional
crystal structure undergoes a transition to superconductivity at =0.6--0.9
K. Its electronic transport properties in the normal state are studied in the
temperature range 1.3--270 K and in magnetic fields up to 11 T. The temperature
variation of the resistivity is weak () in the investigated temperature
range. Nonmonotonic behavior of the resistivity is observed which is
characterized by two local maxima at 2 K and 30 K. The temperature
dependence of the resistivity is interpreted as an interplay of weak
localization, weak antilocalization, and electron-electron interaction effects
in the diffusion and the Cooper channel. The temperature dependence of the
dephasing time extracted from the magnetoresistance data is
determined by the electron-phonon interaction. The saturation of in
the low-temperature limit correlates with of the individual crystal and
is ascribed to the scattering on magnetic impurities.Comment: 8 pages, 6 figure
The layered lanthanum carbide halide superconductors La2C2(X,X′)2 (X,X′ = Cl, Br, I): Neutron powder diffraction characterization and electronic properties.
The rare-earth metal carbide halide superconductors RE<sub>2</sub>C<sub>2</sub>X<sub>2</sub> (RE = Y, La; X = Cl, Br, I)
The CRESST dark matter search
The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) experiment at the Gran Sasso Laboratory will search for dark matter WIMPs using cryogenic detectors. In the first stage we will use four 262 g sapphire crystals with thresholds of about 0.5 keV. This low threshold gives us sensitivity to WIMP masses below 10 GeV, making CRESST complementary to other dark matter searches. The main installation in Gran Sasso is now complete and we report on the first detector tests