Phase Modulators Based on High Mobility Ambipolar ReSe Field-Effect Transistors.

We fabricated ambipolar field-effect transistors (FETs) from multi-layered triclinic ReSe, mechanically exfoliated onto a SiO layer grown on p-doped Si. In contrast to previous reports on thin layers (~2 to 3 layers), we extract field-effect carrier mobilities in excess of 10 cm/Vs at room temperature in crystals with nearly ~10 atomic layers. These thicker FETs also show nearly zero threshold gate voltage for conduction and high ON to OFF current ratios when compared to the FETs built from thinner layers.

Resonant Raman and Exciton Coupling in High-Quality Single Crystals of Atomically Thin Molybdenum Diselenide Grown by Vapor-Phase Chalcogenization.

We report a detailed investigation on Raman spectroscopy in vapor-phase chalcogenization grown, high-quality single-crystal atomically thin molybdenum diselenide samples. Measurements were performed in samples with four different incident laser excitation energies ranging from 1.95 eV ⩽ E ⩽ 2.

Ultrafast structural evolution and formation of linear carbon chains in single-walled carbon nanotube networks by femtosecond laser irradiation.

Inter-allotropic structural transformation of sp structured nanocarbon is a topic of fundamental and technological interest in scalable nanomanufacturing. Such modifications usually require extremely high temperature or high-energy irradiation, and are usually a destructive and time-consuming process. Here, we demonstrate a method for engineering a molecular structure of single-walled carbon nanotubes (SWNTs) and their network properties by femtosecond laser irradiation.

Persistence of strong and switchable ferroelectricity despite vacancies.

Vacancies play a pivotal role in affecting ferroelectric polarization and switching properties, and there is a possibility that ferroelectricity may be utterly eliminated when defects render the system metallic. However, sufficient quantitative understandings of the subject have been lacking for decades due to the fact that vacancies in ferroelectrics are often charged and polarization in charged systems is not translationally invariant. Here we perform first-principles studies to investigate the influence of vacancies on ferroelectric polarization and polarization switching in prototypical BaTiO of tetragonal symmetry.

Predicted coupling of the electromagnetic angular momentum density with magnetic moments.

Analytical derivations are developed to demonstrate that (i) the angular moment density associated with an electromagnetic field can directly couple with magnetic moments to produce a physical energy, (ii) this direct coupling explains known, subtle phenomena, including some recently predicted in magnetoelectric materials, and (iii) this coupling also results in novel effects, such as the occurrence of a magnetic anisotropy that is driven by antiferroelectricity.