64,334 research outputs found
Optoelectronics of Inverted Type-I CdS/CdSe Core/Crown Quantum Ring
Inverted type-I heterostructure core/crown quantum rings (QRs) are
quantum-efficient luminophores, whose spectral characteristics are highly
tunable. Here, we study the optoelectronic properties of type-I core/crown
CdS/CdSe QRs in the zincblende phase - over contrasting lateral size and crown
width. For this we inspect their strain profiles, transition energies,
transition matrix elements, spatial charge densities, electronic bandstructure,
band-mixing probabilities, optical gain spectra, maximum optical gains and
differential optical gains. Our framework uses an effective-mass envelope
function theory based on the 8-band kp method employing the valence
force field model for calculating the atomic strain distributions. The gain
calculations are based on the density-matrix equation and take into
consideration the excitonic effects with intraband scattering. Variations in
the QR lateral size and relative widths of core and crown (ergo the
composition) affect their energy levels, band-mixing probabilities, optical
transition matrix elements, emission wavelengths/intensity, etc. The optical
gain of QRs is also strongly dimension and composition dependent with further
dependency on the injection carrier density causing band-filling effect. They
also affect the maximum and differential gain at varying dimensions and
compositions.Comment: Published in AIP Journal of Applied Physics (11 pages, 7 figures
Palmatine inhibits TRIF-dependent NF-kB pathway against inflammation induced by LPS in goat endometrial epithelial cells
Extracting high fidelity quantum computer hardware from random systems
An overview of current status and prospects of the development of quantum
computer hardware based on inorganic crystals doped with rare-earth ions is
presented. Major parts of the experimental work in this area has been done in
two places, Canberra, Australia and Lund, Sweden, and the present description
follows more closely the Lund work. Techniques will be described that include
optimal filtering of the initially inhomogeneously broadened profile down to
well separated and narrow ensembles, as well as the use of advanced
pulse-shaping in order to achieve robust arbitrary single-qubit operations with
fidelities above 90%, as characterized by quantum state tomography. It is
expected that full scalability of these systems will require the ability to
determine the state of single rare-earth ions. It has been proposed that this
can be done using special readout ions doped into the crystal and an update is
given on the work to find and characterize such ions. Finally, a few aspects on
the possibilities for remote entanglement of ions in separate
rare-earth-ion-doped crystals are considered.Comment: 19 pages, 9 figures. Written for The Proceedings of the
Nobelsymposium on qubits for future quantum computers, Gothenburg, May-0
A study on inclusion formation mechanism in alpha-LiIO sub 3 crystals
The spatial distribution of inclusions in alpha-LiIO3 crystals by means of an argon laser beam scanning technique is studied. The effects of crystal dimensions and solution fluid flow on the inclusion formation in the alpha-LiIO3 crystals were observed. It was further shown that the fluid flow plays an important role in the formation of inclusions. The results obtained were further applied and verified by growing a perfect alpha-LiIO3 single crystal. An experimental foundation for further theoretical studies on the causes of inclusions may be provided
Bias-induced insulator-metal transition in organic electronics
We investigate the bias-induced insulator-metal transition in organic
electronics devices, on the basis of the Su-Schrieffer-Heeger model combined
with the non-equilibrium Green's function formalism. The insulator-metal
transition is explained with the energy levels crossover that eliminates the
Peierls phase and delocalizes the electron states near the threshold voltage.
This may account for the experimental observations on the devices that exhibit
intrinsic bistable conductance switching with large on-off ratio.Comment: 6 pages, 3 figures. To appear in Applied Physics Letter
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