796 research outputs found
Photoconductance of a submicron oxidized line in surface conductive single crystalline diamond
We report on sub-bandgap optoelectronic phenomena of hydrogen-terminated
diamond patterned with a submicron oxidized line. The line acts as an energy
barrier for the two-dimensional hole gas located below the hydrogenated diamond
surface. A photoconductive gain of the hole conductivity across the barrier is
measured for sub-bandgap illumination. The findings are consistent with
photogenerated electrons being trapped in defect levels within the barrier. We
discuss the spatial and energetic characteristics of the optoelectronic
phenomena, as well as possible photocurrent effects
Detection of microseismic compressional (P) body waves aided by numerical modeling of oceanic noise sources
Among the different types of waves embedded in seismic noise, body waves present appealing properties but are still challenging to extract. Here we first validate recent improvements in numerical modeling of microseismic compressional (P) body waves and then show how this tool allows fast detection and location of their sources. We compute sources at ~0.2 Hz within typical P teleseismic distances (30-90°) from the Southern California Seismic Network and analyze the most significant discrete sources. The locations and relative strengths of the computed sources are validated by the good agreement with beam-forming analysis. These 54 noise sources exhibit a highly heterogeneous distribution, and cluster along the usual storm tracks in the Pacific and Atlantic oceans. They are mostly induced in the open ocean, at or near water depths of 2800 and 5600 km, most likely within storms or where ocean waves propagating as swell meet another swell or wind sea. We then emphasize two particularly strong storms to describe how they generate noise sources in their wake. We also use these two specific noise bursts to illustrate the differences between microseismic body and surface waves in terms of source distribution and resulting recordable ground motion. The different patterns between body and surface waves result from distinctive amplification of ocean wave-induced pressure perturbation and different seismic attenuation. Our study demonstrates the potential of numerical modeling to provide fast and accurate constraints on where and when to expect microseismic body waves, with implications for seismic imaging and climate studies. © 2013. American Geophysical Union. All Rights Reserved.This work was supported by the European Research Council (IOWAGA project), the Program >Investment for the future” Labex Mer (grant ANR-10-LABX-19-01), and the Consolider-Ingeno (Topo-Iberia). M.O. performed the data analysis while visiting the Domaines Océanique laboratorPeer Reviewe
Electrical detection of spin echoes for phosphorus donors in silicon
The electrical detection of spin echoes via echo tomography is used to
observe decoherence processes associated with the electrical readout of the
spin state of phosphorus donor electrons in silicon near a SiO interface.
Using the Carr-Purcell pulse sequence, an echo decay with a time constant of
is observed, in good agreement with theoretical modeling
of the interaction between donors and paramagnetic interface states. Electrical
spin echo tomography thus can be used to study the spin dynamics in realistic
spin qubit devices for quantum information processing.Comment: 14 pages, 3 figure
- …