4,780 research outputs found
Nearly Massless Electrons in the Silicon Interface with a Metal Film
We demonstrate the realization of nearly massless electrons in the most
widely used device material, silicon, at the interface with a metal film. Using
angle-resolved photoemission, we found that the surface band of a monolayer
lead film drives a hole band of the Si inversion layer formed at the interface
with the film to have nearly linear dispersion with an effective mass about 20
times lighter than bulk Si and comparable to graphene. The reduction of mass
can be accounted for by repulsive interaction between neighboring bands of the
metal film and Si substrate. Our result suggests a promising way to take
advantage of massless carriers in silicon-based thin-film devices, which can
also be applied for various other semiconductor devices.Comment: 4 pages, 4 figures, accepted for publication in Physical Review
Letter
The role of glass dynamics in the anomaly of the dielectric function of solid helium
We propose that acousto-optical coupling of the electric field to strain
fields around defects in disordered He is causing an increase of the
dielectric function with decreasing temperature due to the arrested dynamics of
defect excitations. A distribution of such low-energy excitations can be
described within the framework of a glass susceptibility of a small volume
fraction inside solid He. Upon lowering the temperature the relaxation time
of defects diverges and an anomaly occurs in the dielectric function
when . Since satisfies the Kramers-Kronig relation, we predict an accompanying peak in
the imaginary part of at the same temperature, where the
largest change in the amplitude has been seen at fixed frequency. We also
discuss recent measurements of the amplitude of the dynamic dielectric function
that indicate a low-temperature anomaly similar to the one seen in the
resonance frequency of the torsional oscillator and shear modulus experiments.Comment: 4 pages, 2 figure
Cross-genotype protection of live-attenuated vaccine candidate for severe fever with thrombocytopenia syndrome virus in a ferret model
Severe fever with thrombocytopenia syndrome (SFTS) virus (SFTSV) is an emerging tick-borne virus classified within the Banyangvirus genus. SFTS disease has been reported throughout East Asia since 2009 and is characterized by high fever, thrombocytopenia, and leukopenia and has a 12 to 30% case fatality rate. Due to the recent emergence of SFTSV, there has been little time to conduct research into preventative measures aimed at combatting the virus. SFTSV is listed as one of the World Health Organization’s Prioritized Pathogens for research into antiviral therapeutics and vaccine development. Here, we report 2 attenuated recombinant SFTS viruses that induce a humoral immune response in immunized ferrets and confer complete cross-genotype protection to lethal challenge. Animals infected with rHB29NSsP102A or rHB2912aaNSs (both genotype D) had a reduced viral load in both serum and tissues and presented without high fever, thrombocytopenia, or mortality associated with infection. rHB29NSsP102A- or rHB2912aaNSs-immunized animals developed a robust anti-SFTSV immune response against cross-genotype isolates of SFTSV. This immune response was capable of neutralizing live virus in a focus-reduction neutralization test (FRNT) and was 100% protective against a cross-genotype lethal challenge with the CB1/2014 strain of SFTSV (genotype B). Thus, using our midsized, aged ferret infection model, we demonstrate 2 live attenuated vaccine candidates against the emerging pathogen SFTSV
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