Observation of the superconducting proximity effect in Nb/InAs and NbNx/InAs by Raman scattering

URL:http://link.aps.org/doi/10.1103/PhysRevB.66.134530 DOI:10.1103/PhysRevB.66.134530High-quality thin Nb and NbN films (60-100 Å) are grown on (100) n+-InAs (n=1019cm-3) substrates by dc-magnetron sputter deposition. Studies of the electronic properties of interfaces between the superconductor and the semiconductor are done by Raman scattering measurements. The superconducting proximity effect at superconductor-semiconductor interfaces is observed through its impact on inelastic light scattering intensities originating from the near-interface region of InAs. The InAs longitudinal optical phonon LO mode (237cm-1) and the plasmon-phonon coupled modes L- (221cm-1) and L+ (1100 to 1350cm-1), for n+=1×1019-2×1019cm-3 are measured. The intensity ratio of the LO mode (associated with the near-surface charge accumulation region, in InAs) to that of the L- mode (associated with bulk InAs), is observed to increase by up to 40% below the superconducting transition temperature. This temperature-dependent change in light scattering properties is only observed with high quality superconducting films and when the superconductor and the semiconductor are in good electrical contact. A few possible mechanisms of the observed effect are proposed.We gratefully acknowledge support from the United States Department of Energy through Materials Research Laboratory~Grant No. DEFG02-96ER45439! ~I.V.R., A.C.A., L.H.G., T.A.T., J.F.D., P.W.B., J.F.K.!, and from the United States Department of Energy through Midwest Superconductivity Consortium ~MISCON! ~Grant No. DE FG02-90ER45427! and the NSF ~Grant No. DMR 96-23827! ~S.W.H., P.F.M.!. SEM, XRD, XPS, and RBS materials characterizations were performed at the Center for Microanalysis of Materials and Microfabrication Center at Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana- Champaign ~Grant No. DE FG02-96ER45439!. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin company, for the United States Department of Energy under Contract No. DE-AC04-94AL85000

The Physics of the B Factories

“The Physics of the B Factories” describes a decade long effort of physicists in the quest for the precise determination of asymmetry — broken symmetry — between particles and anti-particles. We now recognize that the matter we see around us is the residue — one part in a billion — of the matter and antimatter that existed in the early universe, most of which annihilated into the cosmic background radiation that bathes us. But the question remains: how did the baryonic matter-antimatter asymmetry arise? This book describes the work done by some 1000 physicists and engineers from around the globe on two experimental facilities built to test our understanding of this phenomenon, one at the SLAC National Accelerator Laboratory in California, USA, and a second at the KEK Laboratory, Tsukuba, Japan, and what we have learned from them in broadening our understanding of nature

The BABAR detector: Upgrades, operation and performance

The BaBar detector operated successfully at the PEP-II asymmetric e^+e^− collider at the SLAC National Accelerator Laboratory from 1999 to 2008. This report covers upgrades, operation, and performance of the collider and the detector systems, as well as the trigger, online and offline computing, and aspects of event reconstruction since the beginning of data taking

A Metabolomic Approach to the Study of Wine Micro-Oxygenation

Wine micro-oxygenation is a globally used treatment and its effects were studied here by analysing by untargeted LC-MS the wine metabolomic fingerprint. Eight different procedural variations, marked by the addition of oxygen (four levels) and iron (two levels) were applied to Sangiovese wine, before and after malolactic fermentation

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C

Characterizing blood metabolomics profiles associated with self-reported food intakes in female twins

Using dietary biomarkers in nutritional epidemiological studies may better capture exposure and improve the level at which diet-disease associations can be established and explored. Here, we aimed to identify and evaluate reproducibility of novel biomarkers of reported habitual food intake using targeted and non-targeted metabolomic blood profiling in a large twin cohort. Reported intakes of 71 food groups, determined by FFQ, were assessed against 601 fasting blood metabolites in over 3500 adult female twins from the TwinsUK cohort. For each metabolite, linear regression analysis was undertaken in the discovery group (excluding MZ twin pairs discordant [≥1 SD apart] for food group intake) with each food group as a predictor adjusting for age, batch effects, BMI, family relatedness and multiple testing (1.17x10-6 = 0.05/[71 food groups x 601 detected metabolites]). Significant results were then replicated (non-targeted: P<0.05; targeted: same direction) in the MZ discordant twin group and results from both analyses meta-analyzed. We identified and replicated 180 significant associations with 39 food groups (P<1.17x10-6), overall consisting of 106 different metabolites (74 known and 32 unknown), including 73 novel associations. In particular we identified trans-4-hydroxyproline as a potential marker of red meat intake (0.075[0.009]; P = 1.08x10-17), ergothioneine as a marker of mushroom consumption (0.181[0.019]; P = 5.93x10-22), and three potential markers of fruit consumption (top association: apple and pears): including metabolites derived from gut bacterial transformation of phenolic compounds, 3-phenylpropionate (0.024[0.004]; P = 1.24x10-8) and indolepropionate (0.026[0.004]; P = 2.39x10-9), and threitol (0.033[0.003]; P = 1.69x10-21). With the largest nutritional metabolomics dataset to date, we have identified 73 novel candidate biomarkers of food intake for potential use in nutritional epidemiological studies. We compiled our findings into the DietMetab database (http://www.twinsuk.ac.uk/dietmetab-data/), an online tool to investigate our top associations