Materials Literature
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We apply spinning-disc picometrology to measure the complex refractive index of graphene on thermal oxide on silicon. The refractive index varies from n = 2.4-1.0i at 532 nm to n = 3.0-1.4i at 633 nm at room temperature. The dispersion is five times stronger than bulk graphite (2.67-1.34i to 2.73-1.42i from 532 nm to…
Using first-principles techniques, we calculate the renormalization of the electron Fermi velocity and the vibrational lifetimes arising from electron-phonon interactions in doped bilayer graphene and in graphite and compare the results with the corresponding quantities in graphene. For similar levels of doping, the F…
Properties of electrons in superlattices (SLs) of a finite length are described using standing waves resulting from the fixed boundary conditions (FBCs) at both ends. These electron properties are compared with those predicted by the standard treatments using running waves (Bloch states) resulting from the cyclic boun…
Vanadium dioxide, VO2, and its metal-insulator transition at T=340K continues to receive considerable interest. The question whether the physics of the insulating low-temperature phase is dominated by the Mott or the Peierls scenario, i.e. by correlation or band effects, is still under debate. A recent cluster dynamic…
The potential experienced by transverse domain walls (TDWs) in the vicinity of asymmetric constrictions or protrusions in thin Permalloy nanowires is probed using spatially resolved magneto-optical Kerr effect measurements. Both types of traps are found to act as pinning centers for DWs. The strength of pinning is fou…
We study the magnetic and electronic properties of defects in ${\text{SnO}}_{2}$ using pseudopotential and all electron methods. Our calculations show that bulk ${\text{SnO}}_{2}$ is nonmagnetic, but it shows magnetism with a magnetic moment around $4.00{\ensuremath{\mu}}_{B}$ due to Sn vacancy $({V}_{\text{Sn}})$. Th…
A critical assessment of the OPBE functional is made for its performance for the geometries and spin-states of iron complexes. In particular, we have examined its performance for the geometry of first-row transition-metal (di)halides (MnX2, FeX2, CoX2, NiX2, CuX, X=[F, Cl]), whose results were previously [J. Chem. The…
Raman spectra were measured for mono-, bi-, and trilayer graphene grown on SiC by solid state graphitization, whereby the number of layers was preassigned by angle-resolved ultraviolet photoemission spectroscopy. It was found that the only unambiguous fingerprint in Raman spectroscopy to identify the number of layers…
The ultrafast relaxation and recombination dynamics of photogenerated electrons and holes in epitaxial graphene are studied using optical-pump terahertz-probe spectroscopy. The conductivity in graphene at terahertz frequencies depends on the carrier concentration as well as the carrier distribution in energy. Time-res…
Highly fluorescent conjugated polymer dots were developed for demanding applications such as fluorescence imaging in live cells. These nanoparticles exhibit small particle diameters, extraordinary fluorescence brightness, and excellent photostability. Single particle fluorescence imaging and kinetic studies indicate m…
Optical reflectivity and transmission measurements over photon energies between 0.2 and 1.2 eV were performed on single-crystal graphene samples on a SiO2 substrate. For photon energies above 0.5 eV, graphene yielded a spectrally flat optical absorbance of (2.3+/-0.2)%. This result is in agreement with a constant abso…
Boron oxide with a melting point of 450°C was used as an additive to study liquid‐phase sintering of nanocrystalline titania, both in bulk as well as in thin films. The liquid phase has two salient effects. (I) It leads to enhanced transformation of anatase to rutile in the bulk material, accompanied by strong grain g…
Different types of gels are currently used as crystallization media avoiding convective fluid motion and sedimentation of crystals, two properties that are beneficial when seeking crystals of the highest quality for structural studies. We show in this paper the compatibility of the main precipitating agents, buffers,…
Instabilities often arise in the sedimentation of colloidal particles, even when using the density gradient technique. These instabilities occur at volume fractions as low as 10 −3 or 10 −4, causing mixing of particles throughout the suspension, rather than the smooth sedimentation of particles. Here, we show that the…
The photophysical study of platinum carbonyl clusters shows that these clusters exhibit double emitting properties in the visible and near-infrared spectral region for single excitation wavelength. When deposited on glass, they self-assemble into long nanowires or spherical aggregates which still exhibit fluorescence…
Bacterial RibG is a potent target for antimicrobial agents, because it catalyzes consecutive deamination and reduction steps in the riboflavin biosynthesis. In the N-terminal deaminase domain of Bacillus subtilis RibG, structure-based mutational analyses demonstrated that Glu51 and Lys79 are essential for the deaminas…
As solid oxide fuel cell (SOFC) technology is rapidly evolving, high-fidelity mathematical models based on physical principles have become essential tools for SOFC system design and analysis. While several SOFC models have been developed by different groups using different modeling assumptions, little analysis of the…
A novel contact-free magnetoelastic microsensor for diagnosing failing orthopedic implants is introduced. It uses an implant-embedded 30-mum-thick MetGlas-2826 film and a sensing coil placed 30 mm away from the film. Implant loading generates thin-film magnetoelastic response, passively (contact-free) detected as volt…
Steady state permeability coefficients P of carbon dioxide (CO 2 ) in polystyrene (PS) and PS nanocomposites and their corresponding foams at 0.10 MPa (gauge pressure) and three different temperatures were measured. Permeability coefficients of foams are about 1 order of magnitude higher than those of corresponding pl…
Relativistic calculations within the spin-orbit mean-field (SOMF) approximation, the zero-order regular approximation (ZORA), and the scalar relativistic method based on the Pauli Hamiltonian were performed for the prediction and interpretation of the electronic g tensor and (13)C hyperfine tensor for a set of model p…