Alternative techniques are presented for the evaluation of the electron momentum density (EMD) of crystalline systems from ab initio linear combination of atomic-orbitals calculations performed in the frame of one-electron self-consistent-field Hamiltonians. Their respective merits and drawbacks are analyzed with reference to two periodic systems with very different electronic features: the ful...

Functionalization of [60]fullerene with liquid-crystalline dendrimers and a dibutylaniline-based phenylenevinylene moiety leads to supramolecular materials, the fluorescence of which responds to acid-base stimuli.

A key challenge in photovoltaics today is to develop cell technologies with both higher efficiencies and lower fabrication costs than incumbent crystalline silicon (c-Si) single-junction cells. While tandem cells have higher efficiencies than c-Si alone, it is generally challenging to find a low-cost, high-performance material to pair with c-Si. However, the recent emergence of 22% efficient pe...

The vast majority of commercial polyolefins are semi-crystalline materials. Depending on the chemical composition and tacticity, their melting temperatures range from ambient to temperatures exceeding 160 C. Polyolefins form various crystalline structures that can be investigated with microscopic, spectroscopic and scattering techniques. When a semi-crystalline polyolefin is dissolved in a solv...

Crystallization, commonly defined as a process of formation of a crystalline solid from a supersaturated solution, melt or vapor phase, is an old technique widely used in laboratory and in industrial processes to separate and purify substances. In various modern industries, crystalline forms with a certain habit, size and structure, constitute the basic materials for the production of highly so...

Topological crystalline insulators (TCIs) are insulating materials whose topological property relies on generic crystalline symmetries. Based on first-principles calculations, we study a three-dimensional (3D) crystal constructed by stacking two-dimensional TCI layers. Depending on the interlayer interaction, the layered crystal can realize diverse 3D topological phases characterized by two mir...

In simple crystalline materials, plastic deformation mostly takes place by the movement of dislocations. Although the underlying mechanisms in these materials are well explored, in complex metallic alloys--crystalline solids containing up to thousands of atoms per unit cell--the defects and deformation mechanisms remain essentially unknown. Owing to the large lattice parameters of these materia...

Dislocation dynamics dictate the mechanical behavior of materials. Dislocations in periodic crystalline materials have been well documented. On the contrary, dislocations in cylindrical carbon nanotubes, particularly in multiwalled carbon nanotubes (MWCNTs), remain almost unexplored. Here we report that a room temperature 1/2<0001> sessile dislocation in a MWCNT becomes highly mobile, as charac...