690 research outputs found
Universal optimal hole-doping concentration in single-layer high-temperature cuprate superconductors
We argue that in cuprate physics there are two types, hole content per
CuO plane () and the corresponding hole content per unit volume
(), of hole-doping concentrations for addressing physical properties
that are two-dimensional (2D) and three-dimensional (3D) in nature,
respectively. We find that superconducting transition temperature ()
varies systematically with as a superconducting \textquotedblleft
\textquotedblright with a universal optimal hole-doping concentration
= 1.6 10 cm for single-layer high
temperature superconductors. We suggest that determines the
upper bound of the electronic energy of underdoped single-layer high-
cuprates.Comment: 8 pages, 4 figures; added references ;accepted for the publication in
Supercond. Sci. Technol ; Ref. 13 is revise
Far-infrared measurements of oxygen-doped polycrystalline La2CuO4.0315 superconductor under slow-cooled and fast-cooled conditions
We have studied the far-infrared (far-IR) charge dynamics of an equilibrated
pure oxygen doped La2CuO4+0.0315 under slow-cooled and fast-cooled conditions.
The superconducting transition temperature (Tc) for the slow-cooled and that
for the fast-cooled processes were respectively found to be close to the two
intrinsic Tc's: One at 30 K and the other at 15 K. Direct comparison with our
previous results and other far-IR and Raman studies on single crystalline
La2-xSrxCuO4, we conclude that the topology of the pristine electronic phases
that are responsible for the two intrinsic Tc's is holes arranged into
two-dimensional (2D) square lattices.Comment: Submitted to PR
Observation of the predicted charge collective mode of the Tc = 45 K superconducting phase of La2CuO4+{\delta}
We report the far-infrared (far-IR) observation of the Goldstone mode at ~ 72
cm-1 (~ 9 meV) predicted to exist in the superconducting phase of the
transition temperature (Tc) at 45 K in the La2CuO4-based superconductors. Our
observation furthers the experimental support for the two-component picture
where the localized charge texture, formed at a specific planar hole density
(Ppl), is tied to the HTS at Tc = 15 K, 30 K, and 45 K in a hierarchical
fashion at the so-called "magic" doping level at Ppl = 1/16, 2/16, and 3/16
respectively.Comment: 3 figure
Experimental Observation of Environment-induced Sudden Death of Entanglement
We demonstrate the difference between local, single-particle dynamics and
global dynamics of entangled quantum systems coupled to independent
environments. Using an all-optical experimental setup, we show that, while the
environment-induced decay of each system is asymptotic, quantum entanglement
may suddenly disappear. This "sudden death" constitutes yet another distinct
and counter-intuitive trait of entanglement.Comment: 4 pages, 4 figure
Effects of Dehydration on Freezing Characteristics and Survival in Liquid Nitrogen of Three Recalcitrant Seeds
The recalcitrant seeds rambutan( Nephelium lappaceum). durian (Durio zibethinus) and cempedak
(Artocarpus inleger) have a high critical moisture content (below which ·rapid loss of viability occurs of
27.0%, 26.0% and 37.9%,respectively. The critical moisture for embroys were higher at 39.0%
for rambutan, 53.9% for durian and 43.2% for Cempedak. Differential Thermal analysis of the embroyos
confirmed that their threshhold moistures (below which there is no freezable water) were lower than their critical
moistureS. The Threshhold moistures for rambutan, durian and cempedak embryos were approximately 30%,
32% and 33% respectively. It is suggested that unsuccessful attempts at cryopreservation of embroyos of
'recalcitrant seeds in the past maybe due to the absence of safe window between the high critical moisture
content and the threshhold moisture. This results in freezing injury at the higher moistures and dehydration
injury' at the lower moistures. Potential techniques to overcome this and improve cryopreservation of recalcitrant
seed embryos are discussed
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