Roberto Car

TL;DR: In this article, the stability and electronic properties of composite B[sub x]C[sub y]N[sub z] nanotube heterojunctions were investigated using density functional calculations and semi-empirical approaches.

TL;DR: The first principles methods, density-functional theory and quantum Monte Carlo, have been used to examine the balance between van der Waals (vdW) forces and hydrogen bonding in ambient and high-pressure phases of ice as discussed by the authors.

TL;DR: In this paper, a self-consistent Green's-function total energy calculation was performed to understand the microscopic mechanisms of atomic diffusion in Si, showing that the self-interstitial has negative-$U$ properties, roughly the same formation energy at several sites, small migration barriers, and charge-state instabilities that allow athermal migration along several paths.

TL;DR: On the basis of the partial structure factors, the origin of the first sharp diffraction peak is investigated and affects differently the localization properties of valence and conduction band states, as suggested by experimental mobilities of electrons and holes.

TL;DR: The bending characteristics of functionalized graphene sheets are probed with the tip of an atomic force microscope, suggesting that the folding and bending behavior of the sheets is dominated by pre-existing kink (or even fault) lines consisting of defects and/or functional groups.