20,012 research outputs found
Two-band superconductivity in doped SrTiO films and interfaces
We investigate the possibility of multi-band superconductivity in SrTiO
films and interfaces using a two-dimensional two-band model. In the undoped
compound, one of the bands is occupied whereas the other is empty. As the
chemical potential shifts due to doping by negative charge carriers or
application of an electric field, the second band becomes occupied, giving rise
to a strong enhancement of the transition temperature and a sharp feature in
the gap functions, which is manifested in the local density of states spectrum.
By comparing our results with tunneling experiments in Nb-doped SrTiO, we
find that intra-band pairing dominates over inter-band pairing, unlike other
known multi-band superconductors. Given the similarities with the value of the
transition temperature and with the band structure of LaAlO/SrTiO
heterostructures, we speculate that the superconductivity observed in
SrTiO interfaces may be similar in nature to that of bulk SrTiO,
involving multiple bands with distinct electronic occupations.Comment: revised expanded versio
FM 047-02: a collisional pair of galaxies with a ring
Aims. We investigate the nature of the galaxy pair FM 047-02, which has been
proposed as an archetype of the Solitaire types of peculiar (collisional) ring
galaxies. Methods. The study is based on long-slit spectrophotometric data in
the range of 3500-9500 angstrons obtained with the Gemini Multi-ObjectComment: 07 pages, 06 figures, 02 tables. arXiv admin note: text overlap with
arXiv:1206.071
Optical and Near Infrared Study of the Cepheus E outflow, a very low excitation object
We present images and spectra of the Cepheus E (Cep E) region at both optical
and infrared wavelengths. Only the brightest region of the southern lobe of the
Cep E outflow reveals optical emission, suggesting that the extinction close to
the outflow source plays an important r\^ole in the observed difference between
the optical and IR morphologies. Cep E is a unique object since it provides a
link between the spectroscopic properties of the optical Herbig-Haro (HH)
objects and those of deeply embedded outflows.Comment: Accepted Astron. J., 8 files: paper, tables plus 6 figure
Infrared scintillation yield in gaseous and liquid argon
The study of primary and secondary scintillations in noble gases and liquids
is of paramount importance to rare-event experiments using noble gas media. In
the present work, the scintillation yield in gaseous and liquid Ar has for the
first time been measured in the near infrared (NIR) and visible region, both
for primary and secondary (proportional) scintillations, using Geiger-mode
avalanche photodiodes (G-APDs) and pulsed X-ray irradiation. The primary
scintillation yield of the fast component was measured to be 17000 photon/MeV
in gaseous Ar in the NIR, in the range of 690-1000 nm, and 510 photon/MeV in
liquid Ar, in the range of 400-1000 nm. Proportional NIR scintillations
(electroluminescence) in gaseous Ar have been also observed; their
amplification parameter at 163 K was measured to be 13 photons per drifting
electron per kV. Possible applications of NIR scintillations in high energy
physics experiments are discussed.Comment: 6 pages, 5 figures. Submitted to Europhysics Letter. Revised Figs. 3
and
Case of Odontoma-Related Infection in a Cleidocranial Dysplasia
info:eu-repo/semantics/publishedVersio
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