This paper takes a fundamental view of the electron energy loss spectra of monolayer and few layer MoS2. The dielectric function of monolayer MoS2 is compared to the experimental spectra to give clear criteria for the nature of different signals. Kramers-Krönig analysis allows a direct extraction of the dielectric function from the experimental data. However this analysis is sensitive to slight changes in the normalisation step of the data pre-treatment. Density functional theory provides simulations of the dielectric function for comparison and validation of experimental findings. Simulated and experimental spectra are compared to isolate the and + surface plasmon modes in monolayer MoS2. Single-particle excitations obscure the plasmons in the monolayer spectrum and momentum resolved measurements give indication of indirect interband transitions that are excited due to the large convergence and collection angles used in the experiment.

The exotic internal structure of polar topologies in multiferroic materials offers a rich landscape for materials science research. As the spatial scale of these entities is often subatomic in nature, aberration-corrected transmission electron microscopy (TEM) is the ideal characterization technique. Software to quantify and visualize the slight shifts in atomic placement within unit cells is of paramount importance due to the now routine acquisition of images at such resolution. In the previous ~decade since the commercialization of aberration-corrected TEM, many research groups have written their own code to visualize these polar entities. More recently, open-access Python packages have been developed for the purpose of TEM atomic position quantification. Building on these packages, we introduce the TEMUL Toolkit: a Python package for analysis and visualization of atomic resolution images. Here, we focus specifically on the TopoTEM module of the toolkit where we show an easy to follow, streamlined version of calculating the atomic displacements relative to the surrounding lattice and thus plotting polarization. We hope this toolkit will benefit the rapidly expanding field of topology-based nano-electronic and quantum materials research, and we invite the electron microscopy community to contribute to this open-access project.

Antibiotic resistance has grown significantly in the last three decades, while research and development of new antibiotic classes has languished. Therefore, new chemical frameworks for the control of microbial behavior are urgently required. This study presents a novel suite of compounds, based on a tricyclic 4-hydroxy-2 H -pyrano[3,2- c ]quinoline-2,5(6 H )-dione core, with significant antibiotic activity against the ESKAPE pathogens Staphylococcus aureus and Enterococcus faecalis and the “accidental pathogen” Staphylococcus epidermidis . A potent analogue with an N -heptyl-9- t- Bu substitution pattern emerged as a hit with MIC levels ≤2 μg/mL across four strains of MRSA. In addition, the same compound proved highly potent against Enterococcus spp. (0.25 μg/mL).

Controlled functionalisation of nano-and low-dimensional materials will open possibilities for fabrication of innovative devices, e.g., long aspired single photon sources and devices for quantum metrology based on these materials. Achievement of these is very likely, if nanoscale localised electronic doping compatible with large-scale integrated semiconductor technologies can be achieved. Targeted doping, of nano-tubes and 2-D materials, e.g., graphene and monolayer BN as well as transition metal dichalcogenides (TMDs), has been attempted here via ultra-low energy ion implantation in order to tailor bandstructure and thus opto-electronic properties [1, 2, 3, 4]. TMDs are particularly promising for quantum device purposes, as they possess many unique properties, such as large direct bandgaps, optically addressable spin and valley pseudospin degrees of freedom and large magnetic moments.

No abstract