1,054 research outputs found
Directed Growth of Hydrogen Lines on Graphene: High Throughput Simulations Powered by Evolutionary Algorithm
We set up an evolutionary algorithm combined with density functional
tight-binding (DFTB) calculations to investigate hydrogen adsorption on flat
graphene and graphene monolayers curved over substrate steps. During the
evolution, candidates for the new generations are created by adsorption of an
additional hydrogen atom to the stable configurations of the previous
generation, where a mutation mechanism is also incorporated. Afterwards a
two-stage selection procedure is employed. Selected candidates act as the
parents of the next generation. In curved graphene, the evolution follows a
similar path except for a new mechanism, which aligns hydrogen atoms on the
line of minimum curvature. The mechanism is due to the increased chemical
reactivity of graphene along the minimum radius of curvature line (MRCL) and to
sp bond angles being commensurate with the kinked geometry of hydrogenated
graphene at the substrate edge. As a result, the reaction barrier is reduced
considerably along the MRCL, and hydrogenation continues like a mechanical
chain reaction. This growth mechanism enables lines of hydrogen atoms along the
MRCL, which has the potential to overcome substrate or rippling effects and
could make it possible to define edges or nanoribbons without actually cutting
the material.Comment: 10 pages of main text, 37 pages of supplementary information, 1
supplementary vide
Evidence from scanning tunneling microscopy in support of a structural model for the InSb(001)-c(8×2) surface
In this letter we present evidence from scanning tunneling microscopy studies in support of a recently proposed structural model for the indium-terminated c(8×2) surface of InSb(001). This structural model, by Norris and co-workers, is based on a surface x-ray diffraction study [Surf. Sci. 409, 27 (1998)], and represents a significant departure from previously suggested models for the c(8×2) reconstruction on any (001) surface of the common III–V semiconductor materials. Although filled state images of the InSb(001)-c(8×2) surface have previously been published, empty states image of sufficient quality to extract any meaningful information have not previously been reported. The observations are in excellent agreement with the recently proposed model for this surface reconstruction
Beyond spatial and temporal averages: ecological responses to extreme events may be exacerbated by local disturbances
published_or_final_versio
Imaging of Au nanoparticles within Cypress leaves using absorption edge radiography and micro-CT
Ion transport investigation in poplar leaves by means of nanofocussing refractive lenses and micro-CT
Quantitative synchrotron micro-XRF study of CoTSPc and CuTSPc thin-films deposited on gold by cyclic voltammetry
Gauge Consistent Wilson Renormalization Group I: Abelian Case
A version of the Wilson Renormalization Group Equation consistent with gauge
symmetry is presented. A perturbative renormalizability proof is established. A
wilsonian derivation of the Callan-Symanzik equation is given.Comment: Latex2e, 39 pages, 3 eps figures. Revised version to appear in Int.
J. Mod. Phy
- …