Theoretical analysis of Raman scattering spectra (RS) for single-crystal MoS2 sample and atomically thin MoS2 sample consisting from one to few layers was performed in order to explain the change of MoS2 vibrations at transition from a monoatomic layer to a bulk crystal. Experiments have shown that changes of frequencies of the most intensive bands arising from the in-plane, [Formula: see text]...

Van der Waals (vdW) heterostructures are expected to play a key role in next-generation electronic and optoelectronic devices. In this study, the band alignment of a vdW heterostructure with 2D polar materials was studied using first-principles calculations. As a model case study, single-sided fluorographene (a 2D polar material) on insulating (h-BN) and metallic (graphite) substrates was inves...

Two-dimensional (2D) transition metal dichalcogenide (TMD) nanosheets exhibit remarkable electronic and optical properties. The 2D features, sizable bandgaps and recent advances in the synthesis, characterization and device fabrication of the representative MoS2, WS2, WSe2 and MoSe2 TMDs make TMDs very attractive in nanoelectronics and optoelectronics. Similar to graphite and graphene, the atom...

Van der Waals (vdW) interactions are important in numerous physical, chemical, and biological systems. However, traditional density functional theory (DFT) within local or semi-local approximations can hardly treat this interaction. Among various attempts to handle vdW interactions in DFT, semiempirical correction methods are known to present the advantages of low additional computational costs...

The accurate determination of stacking fault energies (SFE) and associated restoring forces is important for understanding plastic deformation, especially the dislocation emission and motion in metals. In this work, we use density-functional theory (DFT) calculations to, systematically study the all-dimension relaxed atomic models of Mg crystal slip, with a special focus on the “subslip modes” ...

We have computed the surface energies, work functions, and interlayer surface relaxations of clean (111), (100), and (110) surfaces of Al, Cu, Ru, Rh, Pd, Ag, Pt, and Au. We interpret the surface energy from liquid metal measurements as the mean of the solid-state surface energies over these three lowest-index crystal faces. We compare experimental (and random phase approximation) reference val...

Abstract With the outstanding mechanical properties, van der Waals (vdW) materials have attracted extensive attention in research of straintronics past decade. In this perspective, we first review recent progresses with vdW based on three different lattice deformation modes, i.e., in-plane strain, out-of-plane and heterostrain. Then discuss current technique challenges field, finally provide ou...

The fabrication of van der Waals heterostructures, artificial materials assembled by individual stacking of 2D layers, is among the most promising directions in 2D materials research. Until now, the most widespread approach to stack 2D layers relies on deterministic placement methods, which are cumbersome and tend to suffer from poor control over the lattice orientations and the presence of unw...

Elastic properties of materials are an important factor in their integration in applications. Chemical vapor deposited (CVD) monolayer semiconductors are proposed as key components in industrial-scale flexible devices and building blocks of two-dimensional (2D) van der Waals heterostructures. However, their mechanical and elastic properties have not been fully characterized. Here we report high...

This paper gives a review of existing models used by other authors aiming at modeling micromanipulation tasks. It introduces the distinction between surface forces, which act even at distance (van der Waals (VDW), capillary and electrostatic forces) and contact forces, which are closely related to deformation and adhesion. Moreover, it presents our work on VDW and capillary forces: compared to ...