Synthesis of WTe Nanowires with Increased Electron Scattering.

Tungsten ditelluride (WTe) has many interesting properties such as its extremely large nonsaturating magnetoresistance and quantum spin Hall state in the monolayer limit. The anisotropic crystal structure of WTe can allow for isolation of particular crystal directions to study the predicted Weyl states or crystal-symmetry-dependent magnetoresistance when studied at limited dimensions. In particular, the recent demonstration of superconductivity in WTe monolayer suggests that realizing nanowire geometry for WTe may be important to investigate potential Majorana zero modes predicted in one-dimensional topological superconductors.

Thickness and Stacking Sequence Determination of Exfoliated Dichalcogenides (1T-TaS2, 2H-MoS2) Using Scanning Transmission Electron Microscopy.

Layered transition metal dichalcogenides (TMDs) have attracted interest due to their promise for future electronic and optoelectronic technologies. As one approaches the two-dimensional (2D) limit, thickness and local topology can greatly influence the macroscopic properties of a material. To understand the unique behavior of TMDs it is therefore important to identify the number of atomic layers and their stacking in a sample.

Atomic lattice disorder in charge-density-wave phases of exfoliated dichalcogenides (1T-TaS2).

Charge-density waves (CDWs) and their concomitant periodic lattice distortions (PLDs) govern the electronic properties in several layered transition-metal dichalcogenides. In particular, 1T-TaS undergoes a metal-to-insulator phase transition as the PLD becomes commensurate with the crystal lattice. Here we directly image PLDs of the nearly commensurate (NC) and commensurate (C) phases in thin, exfoliated 1T-TaS using atomic resolution scanning transmission electron microscopy at room and cryogenic temperature.

Mode manipulation and near-THz absorptions in binary grating-graphene layer structures.

The excitation and absorption properties of grating coupled graphene surface plasmons were studied. It was found that whether a mode can be excited is mainly determined by the frequency of incident light and the duty ratio of gratings. In the structure consisting graphene bilayer, a blueshift of the excitation frequency existed when the distance between neighbor graphene layer were decreased gradually.