148,032 research outputs found
Influence of Disorder on the Hall Effect in BiSrCuO
The in-plane resistivity and Hall coefficient have been measured for the
single-layer compound BiSrCuO for the whole range of
doping states. The deviation of the Hall coefficient, , from a
high-temperature linear behavior and the temperature dependence of the Hall
angle are both only weakly dependent upon doping, contrasting with
BiSrLaCuO and BiSrCaCuO. This
is in contradiction with former proposals that the transverse transport detects
the formation of incoherent Cooper pairs in the pseudogap state. Conversely,
the analysis of the data using a phenomenological angular dependent scattering
rate clearly allows to distinguish between underdoped and overdoped states, and
we propose that the maximum in simply arises due to the combination of
a large isotropic scattering rate and an anisotropic temperature dependent one
Binary Stellar Population Synthesis Model
Using Yunnan evolutionary population synthesis (EPS) models, we present
integrated colours, integrated spectral energy distributions (ISEDs) and
absorption-line indices defined by the Lick Observatory image dissector scanner
(Lick/IDS) system, for an extensive set of instantaneous-burst binary stellar
populations (BSPs) with interactions. By comparing the results for populations
with and without interactions we show that the inclusion of binary interactions
makes the appearance of the population substantially bluer. This effect raises
the derived age and metallicity of the population.
To be used in the studies of modern spectroscopic galaxy surveys at
intermediate/high spectral resolution, we also present intermediate- (3A) and
high-resolution (~0.3A) ISEDs and Lick/IDS absorption-line indices for BSPs. To
directly compare with observations the Lick/IDS absorption indices are also
presented by measuring them directly from the ISEDs.Comment: 2 pages 2 figure
Resistance noise in Bi_2Sr_2CaCu_2O
The resistance noise in a Bi_2Sr_2CaCu_2O thin film is found to
increase strongly in the underdoped regime. While the increase of the raw
resistance noise with decreasing temperature appears to roughly track the
previously reported pseudogap temperature for this material, standard noise
analysis rather suggests that the additional noise contribution is driven by
the proximity of the superconductor-insulator transition
The Effect of Binary Interactions in Infrared Passbands
We present the integrated J, H, K, L, M and N magnitudes and the colours
involving infrared bands, for an extensive set of instantaneous-burst binary
stellar populations (BSPs) by using evolutionary population synthesis (EPS). By
comparing the results for BSPs WITH and WITHOUT binary interactions we show
that the inclusion of binary interactions makes the magnitudes of populations
larger (fainter) and the integrated colours smaller (bluer) for t > 1Gyr. Also,
we compare our model magnitudes and colours with those of Bruzual & Charlot
(2003, hereafter BC03) and Maraston (2005, hereafter M05). At last, we compare
these model broad colours with Magellanic Clouds globular clusters (GCs) and
Milky Way GCs. In (V-R)-[Fe/H] and (V-I)-[Fe/H] diagrams it seems that our
models match the observations better than those of BC03 and M05.Comment: 2 page 3 figure
Electron transport in interacting hybrid mesoscopic systems
A unified theory for the current through a nanoscale region of interacting
electrons connected to two leads which can be either ferromagnet or
superconductor is presented, yielding Meir-Wingreen-type formulas when applied
to specific circumstances. In such a formulation, the requirement of gauge
invariance for the current is satisfied automatically. Moreover, one can judge
unambiguously what quantities can be measured in the transport experiment
LLAGN and jet-scaling probed with the EVN
Accreting black holes on all mass scales (from stellar to supermassive)
appear to follow a nonlinear relation between X-ray luminosity, radio
luminosity and BH mass, indicating that similar physical processes drive the
central engines in X-ray binaries and active galactic nuclei (AGN). However, in
recent years an increasing number of BH systems have been identified that do
not fit into this scheme. These outliers may be the key to understand how BH
systems are powered by accretion. Here we present results from EVN observations
of a sample of low-luminosity AGN (LLAGN) with known mass that have unusually
high radio powers when compared with their X-ray luminosity.Comment: Presented at the 11th EVN Symposium, Bordeaux, France, 2012 October
9-12. Six pages, including a figure and a table. Final, accepted versio
Current dependent fluctuations in a BiSrCuO thin film
The current dependence of the excess conductivity is measured up to for a BiSrCuO thin film, as a function of doping. It
is found to be anomalously sensitive to the transport current and to behave as
a universal function of in the whole doping range. We discuss these
results in the perspective of a granular superconductor with a gapless-like
behavior
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