| 1. |
- Abelev, Betty, et al.
(author)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Journal article (peer-reviewed)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(author)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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In: Journal of High Energy Physics. - 1029-8479. ; :11
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Journal article (peer-reviewed)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Hertel, Stefan, et al.
(author)
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Tailoring the graphene/silicon carbide interface for monolithic wafer-scale electronics
- 2012
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 3
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Journal article (peer-reviewed)abstract
- Graphene is an outstanding electronic material, predicted to have a role in post-silicon electronics. However, owing to the absence of an electronic bandgap, graphene switching devices with high on/off ratio are still lacking. Here in the search for a comprehensive concept for wafer-scale graphene electronics, we present a monolithic transistor that uses the entire material system epitaxial graphene on silicon carbide (0001). This system consists of the graphene layer with its vanishing energy gap, the underlying semiconductor and their common interface. The graphene/semiconductor interfaces are tailor-made for ohmic as well as for Schottky contacts side-by-side on the same chip. We demonstrate normally on and normally off operation of a single transistor with on/off ratios exceeding 10 4 and no damping at megahertz frequencies. In its simplest realization, the fabrication process requires only one lithography step to build transistors, diodes, resistors and eventually integrated circuits without the need of metallic interconnects.
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| 4. |
- Hop, Paul J., et al.
(author)
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Genome-wide study of DNA methylation shows alterations in metabolic, inflammatory, and cholesterol pathways in ALS
- 2022
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In: Science Translational Medicine. - : American Association for the Advancement of Science. - 1946-6234 .- 1946-6242. ; 14:633
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Journal article (peer-reviewed)abstract
- Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with an estimated heritability between 40 and 50%. DNA methylation patterns can serve as proxies of (past) exposures and disease progression, as well as providing a potential mechanism that mediates genetic or environmental risk. Here, we present a blood-based epigenome-wide association study meta-analysis in 9706 samples passing stringent quality control (6763 patients, 2943 controls). We identified a total of 45 differentially methylated positions (DMPs) annotated to 42 genes, which are enriched for pathways and traits related to metabolism, cholesterol biosynthesis, and immunity. We then tested 39 DNA methylation-based proxies of putative ALS risk factors and found that high-density lipoprotein cholesterol, body mass index, white blood cell proportions, and alcohol intake were independently associated with ALS. Integration of these results with our latest genome-wide association study showed that cholesterol biosynthesis was potentially causally related to ALS. Last, DNA methylation at several DMPs and blood cell proportion estimates derived from DNA methylation data were associated with survival rate in patients, suggesting that they might represent indicators of underlying disease processes potentially amenable to therapeutic interventions.
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| 5. |
- Nagy, Roland, et al.
(author)
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Narrow inhomogeneous distribution of spin-active emitters in silicon carbide
- 2021
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In: Applied Physics Letters. - : AMER INST PHYSICS. - 0003-6951 .- 1077-3118. ; 118:14
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Journal article (peer-reviewed)abstract
- Optically active solid-state spin registers have demonstrated their unique potential in quantum computing, communication, and sensing. Realizing scalability and increasing application complexity require entangling multiple individual systems, e.g., via photon interference in an optical network. However, most solid-state emitters show relatively broad spectral distributions, which hinders optical interference experiments. Here, we demonstrate that silicon vacancy centers in semiconductor silicon carbide (SiC) provide a remarkably small natural distribution of their optical absorption/emission lines despite an elevated defect concentration of approximate to 0.43 mu m - 3. In particular, without any external tuning mechanism, we show that only 13 defects have to be investigated until at least two optical lines overlap within the lifetime-limited linewidth. Moreover, we identify emitters with overlapping emission profiles within diffraction-limited excitation spots, for which we introduce simplified schemes for the generation of computationally relevant Greenberger-Horne-Zeilinger and cluster states. Our results underline the potential of the CMOS-compatible SiC platform toward realizing networked quantum technology applications.
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| 6. |
- Roensch, Sebastian, et al.
(author)
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Drain-current deep level transient spectroscopy investigation on epitaxial graphene/6H-SiC field effect transistors
- 2014
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In: Mater. Sci. Forum. - 9783038350101 ; , s. 436-439
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Conference paper (peer-reviewed)abstract
- The electrically active deep levels in a graphene/silicon carbide field effect transistor (FET) were investigated by drain-current deep level transient spectroscopy (ID-DLTS). An evaluation procedure for ID-DLTS is developed in order to obtain the activation energy, the capture cross section and the trap concentration. We observed three defect centers corresponding to the intrinsic defects E1/E2, Ei and Z1/Z2 in n-type 6H-SiC. The determined parameters have been verified by conventional capacitance DLTS.
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| 7. |
- Sledziewski, Tomasz, et al.
(author)
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Reduction of density of 4H-SiC/SiO2 interface traps by pre-oxidation phosphorus implantation
- 2014
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In: Materials Science Forum. - 9783038350101 ; , s. 575-578
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Conference paper (peer-reviewed)abstract
- The effect of phosphorus (P) on the electrical properties of the 4H-SiC/SiO2 interface was investigated. Phosphorus was introduced by surface-near ion implantation with varying ion energy and dose prior to thermal oxidation. Secondary ion mass spectrometry revealed that only part of the implanted P followed the oxidation front to the interface. A negative flatband shift due to residual P in the oxide was found from C-V measurements. Conductance method measurements revealed a significant reduction of density of interface traps Dit with energy EC-Eit > 0.3 V for P+-implanted samples with [P]interface = 1.5 · 1018 cm-3 in the SiC layer at the interface. .
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