Deterministic band gap in quasi-one-dimensional nanoribbons is prerequisite for their integrated functionalities in high performance molecular-electronics based devices. However, multiple band gaps commonly observed in graphene nanoribbons of the same width, fabricated in same slot of experiments, remain unresolved, and raise a critical concern over scalable production of pristine and/or hetero...

We report a dynamic structure and band engineering strategy with experimental protocols to induce indirect-to-direct band gap transitions and coherently oscillating pure spin-currents in three-dimensional antiferromagnets (AFM) using selective phononic excitations. In the Mott insulator LaTiO3, we show that a photo-induced nonequilibrium phonon mode amplitude destroys the spin and orbitally deg...

We report the influence of uniaxial tensile mechanical strain in the range 0-2.2% on the phonon spectra and bandstructures of monolayer and bilayer molybdenum disulfide (MoS2) two-dimensional crystals. First, we employ Raman spectroscopy to observe phonon softening with increased strain, breaking the degeneracy in the E' Raman mode of MoS2, and extract a Grüneisen parameter of ~1.06. Second, us...

The spin-wave band structure of a two-dimensional bicomponent magnonic crystal, consisting of Co nanodisks partially embedded in a Permalloy thin film, is experimentally investigated along a high-symmetry direction by Brillouin light scattering. The eigenfrequencies and scattering cross sections are interpreted using plane wave method calculations and micromagnetic simulations. At the boundary ...

We propose to synthesize a new class of single-walled nanotubular compounds (SWNCs) and investigate the interplay between their structural and electronic properties using ab initio density functional calculations. SWNCs are composed of cyclacenes of variable diameter interconnected by various linker compounds. Cyclacenes map directly onto and can be viewed as the shortest segments of (n,0) zigz...

Local curvature, or bending, of a graphene sheet is known to increase the chemical reactivity presenting an opportunity for templated chemical functionalisation. Using first-principles calculations based on density functional theory (DFT), we investigate the reaction barrier reduction for the adsorption of atomic hydrogen at linear bends in graphene. We find a significant barrier lowering (≈15%...

In this work facile sol-gel (pechni) method has been successfully established to synthesize Zn4B6O13 nanocrystals which have cubic crystals with lattice parameter: a =7.48 A. The structure and morphology of the obtained material were studied by X-ray diffraction (XRD), Infrared spectra (IR), scanning electron microscopy (SEM) and photoluminescence analysis. The experimental results show a band ...

Ca(x)Zn(1-x)O alloys are potential candidates to achieve wide band-gap, which might significantly promote the band gap engineering and heterojunction design. We performed a crystal structure search for CaO-ZnO system under pressure, using an ab initio evolutionary algorithm implemented in the USPEX code. Four stable ordered Ca(x)Zn(1-x)O structures are found in the pressure range of 8.7-60 GPa....

Electromagnetic wave properties in metamaterials including electromagnetic band gap (EBG) structures have been widely investigated due to their inherent capabilities for developing novel devices in the fields of optics, microwave and antenna engineering. In reality, most of the materials are dispersive or frequency-dependent, on the other hand, it is important to investigate how the performance...