Multifunctional heterostructures constructed using MoS2 and WS2 nanoribbons

Electronic structures of WS2 armchair nanoribbons doped with transition metals

Armchair WS2 nanoribbons are semiconductors with band gaps close to 0.5 eV. If some of the W atoms in the ribbon are replaced by transition metals, the impurity states can tremendously affect the overall electronic structure of the doped ribbon. By using first-principles calculations based on density functional theory, we investigated substitutional doping of Ti, V, Cr, Mn, Fe, and Co at various positions on WS2 ribbons of different widths. We found that Fe-doped ribbons can have two-channel conduction in the middle segment of the ribbon and at the edges, carrying opposite spins separately. Many Co-doped ribbons are transformed into spin filters that exhibit 100% spin-polarized conduction. These results will be useful for spintronics and nanoelectronic circuit design.

Strain-engineering the in-plane electrical anisotropy of GeSe monolayers

The anisotropic ratio of the effective mass and mobility of charge carriers of GeSe monolayer along two principle axes can be controlled by using simple strain conditions.

Lateral heterostructures and one-dimensional interfaces in 2D transition metal dichalcogenides

The growth and exfoliation of two-dimensional (2D) materials have led to the creation of edges and novel interfacial states at the juncture between crystals with different composition or phases. These hybrid heterostructures (HSs) can be built as vertical van der Waals stacks, resulting in a 2D interface, or as stitched adjacent monolayer crystals, resulting in one-dimensional (1D) interfaces. Although most attention has been focused on vertical HSs, increasing theoretical and experimental interest in 1D interfaces is evident. In-plane interfacial states between different 2D materials inherit properties from both crystals, giving rise to robust states with unique 1D non-parabolic dispersion and strong spin-orbit effects. With such unique characteristics, these states provide an exciting platform for realizing 1D physics. Here, we review and discuss advances in 1D heterojunctions, with emphasis on theoretical approaches for describing those between semiconducting transition metal dichalcogenides MX ₂ (with M  =  Mo, W and X  =  S, Se, Te), and how the interfacial states can be characterized and utilized. We also address how the interfaces depend on edge geometries (such as zigzag and armchair) or strain, as lattice parameters differ across the interface, and how these features affect excitonic/optical response. This review is intended to serve as a resource for promoting theoretical and experimental studies in this rapidly evolving field.

Two-dimensional transition metal dichalcogenides as promising anodes for potassium ion batteries from first-principles prediction

Although K possesses a larger atomic radius, its migration barriers on TMD monolayers are much smaller than those of Li and Na ions. Among them, both VS₂ and TiS₂ are suggested to be the best electrode for KIBs.