Jochen Rohrer

Stacking and band structure of van der Waals bonded graphane multilayers

We use density functional theory and the van der Waals density functional (vdW-DF) method to determine the binding separation in bilayer and bulk graphane and study the changes in electronic band structure that arise with the multilayer formation. The calculated binding separation (distance between center-of-mass planes) and binding energy are 4.5 -5.0 angstrom (4.5 - 4.8 angstrom) and 75 - 102 meV/cell (93 - 127 meV/cell) in the bilayer (bulk), depending on the choice of vdW-DF version. We obtain the corresponding band diagrams using calculations in the ordinary generalized gradient approximation for the geometries specified by our vdW-DF results, so probing the indirect effect of vdW forces on electron behavior. We find significant band-gap modifications by up to -1.2 eV (+ 4.0 eV) in various regions of the Brillouin zone, produced by the bilayer (bulk) formation.

Atomistic modelling of zirconium and silicon segregation at twist and tilt grain boundaries in molybdenum

We investigate the influence of Zr and Si segregation on the cohesive strength of grain boundaries (GBs) in molybdenum using density functional theory calculations. A tilt

Structure Sensitivity in the Decomposition of Ethylene Carbonate on Si Anodes

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Stabilization of the γ -Sn phase in tin nanoparticles and nanowires

Σ5(310)[001] and twist

La2CoO4: a new intercalation based cathode material for fluoride ion batteries with improved cycling stability

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Ab initio structure modelling of complex thin-film oxides: thermodynamical stability of TiC/thin-film alumina

Σ5[001] GB in bicrystal geometry are chosen as structural models. We determine the site preference of Zr and Si for segregation in these GBs and define the segregation energy. We quantify the effect of solutes on the stability of the GBs against brittle fracture by means of the Griffith criterion (work of separation). Additionally, the intrinsic bond strength of the GB containing a solute is quantified by means of the theoretical strength. The results show that Zr and Si tend to segregate at the GBs if the low-energy insertion sites are available. However, the work of separation is decreased by the presence of Zr and Si and even in the presence of oxygen, there is no increase of the Griffith energy. Contributions of strain and chemical energy are analysed in order to explain our findings.