Observation of interlayer plasmon polaron in graphene/WS heterostructures.

Harnessing electronic excitations involving coherent coupling to bosonic modes is essential for the design and control of emergent phenomena in quantum materials. In situations where charge carriers induce a lattice distortion due to the electron-phonon interaction, the conducting states get "dressed", which leads to the formation of polaronic quasiparticles. The exploration of polaronic effects on low-energy excitations is in its infancy in two-dimensional materials.

Hexagonal Boron Nitride Slab Waveguides for Enhanced Spectroscopy of Encapsulated 2D Materials.

The layered insulator hexagonal boron nitride (hBN) is a critical substrate that brings out the exceptional intrinsic properties of two-dimensional (2D) materials such as graphene and transition metal dichalcogenides (TMDs). In this work, the authors demonstrate how hBN slabs tuned to the correct thickness act as optical waveguides, enabling direct optical coupling of light emission from encapsulated layers into waveguide modes. Molybdenum selenide (MoSe ) and tungsten selenide (WSe ) are integrated within hBN-based waveguides and demonstrate direct coupling of photoluminescence emitted by in-plane and out-of-plane transition dipoles (bright and dark excitons) to slab waveguide modes.

The Heart Rates and Movement Speed of Specialist Tactical Police During a Multistorey Active Shooter Training Scenario.

Specialist police tactical groups (PTGs) are involved in situations that extend beyond the capability of general duties police and can include responding to active shooter incidents. Due to the nature of their tasks, these officers typically carry and wear additional equipment which can impart an increased physical cost, for which the officers must be prepared. The aim of this study was to examine the heart rate responses and movement speeds of specialist PTG officers during a multistorey active shooter scenario.

Engineering of Nanoscale Heterogeneous Transition Metal Dichalcogenide-Au Interfaces.

Engineering the transition metal dichalcogenide (TMD)-metal interface is critical for the development of two-dimensional semiconductor devices. By directly probing the electronic structures of WS-Au and WSe-Au interfaces with high spatial resolution, we delineate nanoscale heterogeneities in the composite systems that give rise to local Schottky barrier height modulations. Photoelectron spectroscopy reveals large variations (>100 meV) in TMD work function and binding energies for the occupied electronic states.

Magnetotransport in Graphene/PbSnTe Heterostructures: Finding a Way to Avoid Catastrophe.

While heterostructures are ubiquitous tools enabling new physics and device functionalities, the palette of available materials has never been richer. Combinations of two emerging material classes, two-dimensional materials and topological materials, are particularly promising because of the wide range of possible permutations that are easily accessible. Individually, both graphene and PbSnTe (PST) are widely investigated for spintronic applications because graphene's high carrier mobility and PST's topologically protected surface states are attractive platforms for spin transport.

Profiling the absolute and relative strength of a special operations police unit.

Background: Specialist police perform high-risk tasks and are required to have, and maintain, a high level of fitness. The aims of this study were to profile the strength of a specialist police unit and to investigate whether this profile remained constant over an 18-month period.

Methods: Retrospective data for 47 special operations police officers (mean initial weight = 88.

The Relationship Between Strength Measures and Task Performance in Specialist Tactical Police.

Orr, RM, Robinson, J, Hasanki, K, Talaber, KA, Schram, B, and Roberts, A. The relationship between strength measures and task performance in specialist tactical police. J Strength Cond Res 36(3): 757-762, 2022-Specialist tactical police officers (STPOs) carry heavier on-body loads than generalist police officers.

Electronic Structure and Stacking Arrangement of Tungsten Disulfide at the Gold Contact.

There is an intensive effort to control the nature of attractive interactions between ultrathin semiconductors and metals and to understand its impact on the electronic properties at the junction. Here, we present a photoelectron spectroscopy study on the interface between WS films and gold, with a focus on the occupied electronic states near the Brillouin zone center (i.e.

Acoustic cavities in 2D heterostructures.

Two-dimensional (2D) materials offer unique opportunities in engineering the ultrafast spatiotemporal response of composite nanomechanical structures. In this work, we report on high frequency, high quality factor (Q) 2D acoustic cavities operating in the 50-600 GHz frequency (f) range with f × Q up to 1 × 10. Monolayer steps and material interfaces expand cavity functionality, as demonstrated by building adjacent cavities that are isolated or strongly-coupled, as well as a frequency comb generator in MoS/h-BN systems.

Room-Temperature Spin Transport in CdAs.

As the need for ever greater transistor density increases, the commensurate decrease in device size approaches the atomic limit, leading to increased energy loss and leakage currents, reducing energy efficiencies. Alternative state variables, such as electronic spin rather than electronic charge, have the potential to enable more energy-efficient and higher performance devices. These spintronic devices require materials capable of efficiently harnessing the electron spin.

Special Weapons and Tactics Occupational-Specific Physical Assessments and Fitness Measures.

Specialist tactical response police are required to frequently perform physically demanding tasks at high-risk capability levels, emphasizing the need for optimal physical fitness in this population. The aim of this study was to investigate the relationships between select measures of physical fitness and performance on an occupational-specific physical assessment (OSPA). A retrospective analysis on 18 male specialist police candidates (age = 32.

Unexpected Near-Infrared to Visible Nonlinear Optical Properties from 2-D Polar Metals.

Near-infrared-to-visible second harmonic generation from air-stable two-dimensional polar gallium and indium metals is described. The photonic properties of 2D metals, including the largest second-order susceptibilities reported for metals (approaching 10 nm/V), are determined by the atomic-level structure and bonding of two-to-three-atom-thick crystalline films. The bond character evolved from covalent to metallic over a few atomic layers, changing the out-of-plane metal-metal bond distances by approximately ten percent (0.

The Physical Fitness Effects of a Week-Long Specialist Tactical Police Selection Course.

Specialist police tactical teams, like special operations military personnel, are tasked with dangerous, high risk missions which are beyond the scope of general police. Consequently, the selection courses for entry into these teams are physiologically and psychologically demanding. The purpose of this study was to examine the physiological effects of a five-day selection course to aid in candidate preparation and course planning.

Observation of Electrically Tunable van Hove Singularities in Twisted Bilayer Graphene from NanoARPES.

The possibility of triggering correlated phenomena by placing a singularity of the density of states near the Fermi energy remains an intriguing avenue toward engineering the properties of quantum materials. Twisted bilayer graphene is a key material in this regard because the superlattice produced by the rotated graphene layers introduces a van Hove singularity and flat bands near the Fermi energy that cause the emergence of numerous correlated phases, including superconductivity. Direct demonstration of electrostatic control of the superlattice bands over a wide energy range has, so far, been critically missing.

Direct observation of minibands in a twisted graphene/WS bilayer.

Stacking two-dimensional (2D) van der Waals materials with different interlayer atomic registry in a heterobilayer causes the formation of a long-range periodic superlattice that may bestow the heterostructure with properties such as new quantum fractal states or superconductivity. Recent optical measurements of transition metal dichalcogenide (TMD) heterobilayers have revealed the presence of hybridized interlayer electron-hole pair excitations at energies defined by the superlattice potential. The corresponding quasiparticle band structures, so-called minibands, have remained elusive, and no such features have been reported for heterobilayers composed of a TMD and another type of 2D material.

Enabling remote quantum emission in 2D semiconductors via porous metallic networks.

Here we report how two-dimensional crystal (2DC) overlayers influence the recrystallization of relatively thick metal films and the subsequent synergetic benefits this provides for coupling surface plasmon-polaritons (SPPs) to photon emission in 2D semiconductors. We show that annealing 2DC/Au films on SiO results in a reverse epitaxial process where initially nanocrystalline Au films gain texture, crystallographically orient with the 2D crystal overlayer, and form an oriented porous metallic network (OPEN) structure in which the 2DC can suspend above or coat the inside of the metal pores. Both laser excitation and exciton recombination in the 2DC semiconductor launch propagating SPPs in the OPEN film.

Associations between Specialist Tactical Response Police Unit Selection Success and Urban Rush, along with 2.4 km and 10 km Loaded Carriage Events.

Officers serving in specialist tactical response police teams are highly trained personnel who are required to carry heavy loads and perform explosive tasks. The aim of this study was to determine whether performance on a loaded explosive occupational task (urban rush) or distance-based load carriage tasks (2.4 km or 10 km) were indicative of officer success on a specialist selection course (SSC).

Do Barrier Test Results Predict Survival in Specialist Police Tactical Selection Courses?

Entry to specialist police tactical teams is governed by performance on a physically intense and psychologically demanding selection course. The aim of this study was to determine the attributes associated with completion of a specialist police selection course. Data pertaining to 18 candidates was obtained including 1 min push-ups, loaded pull-ups, loaded 30 m crawl, agility run, 1.

Chemistries for Making Additive Nanolithography in OrmoComp Permissive for Cell Adhesion and Growth.

Two-photon lithography allows writing of arbitrary nanoarchitectures in photopolymers. This design flexibility opens almost limitless possibilities for biological studies, but the acrylate-based polymers frequently used do not allow for adhesion and growth of some types of cells. Indeed, we found that lithographically defined structures made from OrmoComp do not support E18 murine cortical neurons.

Oxygen-Induced In Situ Manipulation of the Interlayer Coupling and Exciton Recombination in BiSe/MoS 2D Heterostructures.

Two-dimensional (2D) heterostructures are more than a sum of the parent 2D materials, but are also a product of the interlayer coupling, which can induce new properties. In this paper, we present a method to tune the interlayer coupling in BiSe/MoS 2D heterostructures by regulating the oxygen presence in the atmosphere, while applying laser or thermal energy. Our data suggest that the interlayer coupling is tuned through the diffusive intercalation and deintercalation of oxygen molecules.

Aerobic Fitness is of Greater Importance than Strength and Power in the Load Carriage Performance of Specialist Police.

Police officers are required to carry external loads as part of their occupation. One means of preparing officers to carry loads is through physical conditioning. The aim of this study was to investigate whether strength, power or aerobic endurance had the greatest association with load carriage performance.

Profiling the metabolic fitness of a special operations police unit.

Objectives: Fitness is essential to specialist police forces, who have higher occupational demands than general police, and vital to performance and mission success. However, little research has been done profiling the metabolic fitness of these units and how they compare to other populations. The objective of this study was to profile the aerobic fitness of a specialist police unit.

Work Function Variations in Twisted Graphene Layers.

By combining optical imaging, Raman spectroscopy, kelvin probe force microscopy (KFPM), and photoemission electron microscopy (PEEM), we show that graphene's layer orientation, as well as layer thickness, measurably changes the surface potential (Φ). Detailed mapping of variable-thickness, rotationally-faulted graphene films allows us to correlate Φ with specific morphological features. Using KPFM and PEEM we measure ΔΦ up to 39 mV for layers with different twist angles, while ΔΦ ranges from 36-129 mV for different layer thicknesses.

Protection from Below: Stabilizing Hydrogenated Graphene Using Graphene Underlayers.

We show that dehydrogenation of hydrogenated graphene proceeds much more slowly for bilayer systems than for single layer systems. We observe that an underlayer of either pristine or hydrogenated graphene will protect an overlayer of hydrogenated graphene against a number of chemical oxidants, thermal dehydrogenation, and degradation in an ambient environment over extended periods of time. Chemical protection depends on the ease of oxidant intercalation, with good intercalants such as Br demonstrating much higher reactivity than poor intercalants such as 1,2-dichloro-4,5-dicyanonbenzoquinone (DDQ).

Enhancing the stiffness of vertical graphene sheets through ion beam irradiation and fluorination.

Many applications of graphene can benefit from the enhanced mechanical robustness of graphene-based components. We report how the stiffness of vertical graphene (VG) sheets is affected by the introduction of defects and fluorination, both separately and combined. The defects were created using a high-energy ion beam while fluorination was performed in a XeF etching system.