1,173 research outputs found
Photodarkening of amorphous selenium under high pressure
The photodarkening phenomena of amorphous Se have been studied by the optical absorption coefficient, sound velocity and attenuation measurements. The light illumination at low temperatures induces the photodarkening, and the photodarkened state is completely recovered by annealing near 306 K corresponding to the glass transition temperature. The photodarkening is enhanced by application of pressure. The sound velocity decreases and the sound attenuation increases by the illumination at low temperature. These suggest that a structural disorder increases in the photodarkened state. Three stages are observed for the recovery process of the photodarkened specimen. The photodarkening and the recovery process are discussed on the basis of VAP (valence alternative pair) model.<br /
Phase separation in the vicinity of the surface of -(BEDT-TTF)Cu[N(CN)]Br by fast cooling
Partial suppression of superconductivity by fast cooling has been observed in
the organic superconductor -(BEDT-TTF)Cu[N(CN)]Br by two means:
a marked sample size effect on the magnetic susceptibility and direct imaging
of insulating regions by scanning microregion infrared reflectance
spectroscopy. Macroscopic insulating regions are found in the vicinity of the
crystalline surface after fast cooling, with diameters of 50--100 m and
depths of a few m. The very large in-plane penetration depth reported to
date ( 24--100 m) can be explained by the existence of the
insulating regions.Comment: Several rhetoric alternations to avoid misleadings. 6 pages, 3
figures. to be publihsed in Phys. Rev.
Optical probe of carrier doping by X-ray irradiation in organic dimer Mott insulator -(BEDT-TTF)Cu[N(CN)Cl
We investigated the infrared optical spectra of an organic dimer Mott
insulator -(BEDT-TTF)Cu[N(CN)]Cl, which was irradiated with
X-rays. We observed that the irradiation caused a large spectral weight
transfer from the mid-infrared region, where interband transitions in the dimer
and Mott-Hubbard bands take place, to a Drude part in a low-energy region; this
caused the Mott gap to collapse. The increase of the Drude part indicates a
carrier doping into the Mott insulator due to irradiation defects. The strong
redistribution of the spectral weight demonstrates that the organic Mott
insulator is very close to the phase border of the bandwidth-controlled Mott
transition.Comment: 4 pages, 4 figure
Improving School Leadership: The Promise of Cohesive Leadership Systems
Describes Wallace grantees' work to create a cohesive leadership system of coordinated policies between states and districts and across state agencies, states' and districts' efforts to forge cohesive policies, and the impact on instructional leadership
In vitro exoantigen from herpetomonas samuelpessoai which protects mice against trypanosoma cruzi infection
Phase separation in the vicinity of the surface of κ-(BEDT-TTF)2Cu[N(CN)2]Br by fast cooling
科研費報告書収録論文(課題番号:17340099/研究代表者:佐々木孝彦/強相関モット系有機導体における不均一電子状態の自己組織的パターン形成の研究
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