Atomically Sharp 1D Interfaces in 2D Lateral Heterostructures of VSe─NbSe Monolayers.

van der Waals heterostructures have emerged as an ideal platform for creating engineered artificial electronic states. While vertical heterostructures have been extensively studied, realizing high-quality lateral heterostructures with atomically sharp interfaces remains a major experimental challenge. Here, we advance a one-pot two-step molecular beam lateral epitaxy approach and successfully synthesize atomically well-defined 1T-VSe─1H-NbSe lateral heterostructures.

On-Surface Synthesis of Triaza[5]triangulene through Cyclodehydrogenation and its Magnetism.

Triangulenes as neutral radicals are becoming promising candidates for future applications such as spintronics and quantum technologies. To extend the potential of the advanced materials, it is of importance to control their electronic and magnetic properties by multiple graphitic nitrogen doping. Here, we synthesize triaza[5]triangulene on Au(111) by cyclodehydrogenation, and its derivatives by cleaving C-N bonds.

On-Surface Synthesis of Silole and Disila-Cyclooctene Derivatives.

The incorporation of Si atoms into organic compounds significantly increases a variety of functionality, facilitating further applications. Recently, on-surface synthesis was introduced into organosilicon chemistry as 1,4-disilabenzene bridged nanostructures were obtained via coupling between silicon atoms and brominated phenyl groups at the ortho position on Au(111). Here, we demonstrate a high generality of this strategy via syntheses of silole derivatives and nanoribbon structures with eight-membered sila-cyclic rings from dibrominated molecules at the bay and peri positions on Au(111), respectively.

Taxonomic notes on the group of Mischocyttarus heliconius Richards 1941, with description of four new species (Hymenoptera: Vespidae, Polistinae).

Mischocyttarus heliconius was described by Richards (1941), being initially assigned to subgenus Kappa, and later to Clypeopolybia. That author subsequently described other similar species, and Silveira (2008) conceived the group as also including M. iperuae Richards, M.

Divergence time analysis of the Neotropical wasp genus Protopolybia Ducke, 1905 (Vespidae, Polistinae, Epiponini) using a Multilocus Phylogenetic Approach.

The genus Protopolybia Ducke was analyzed using a multilocus phylogenetic approach, which confirmed its monophyly. In contrast with the arrangements derived solely from morphological data, however, this analysis divides the genus into only two major clades. The study also presents divergence times for the origin and diversification of Protopolybia, which are related to possible vicariant events occurring in the Amazon biome.

Local probe-induced structural isomerization in a one-dimensional molecular array.

Synthesis of one-dimensional molecular arrays with tailored stereoisomers is challenging yet has great potential for application in molecular opto-, electronic- and magnetic-devices, where the local array structure plays a decisive role in the functional properties. Here, we demonstrate the construction and characterization of dehydroazulene isomer and diradical units in three-dimensional organometallic compounds on Ag(111) with a combination of low-temperature scanning tunneling microscopy and density functional theory calculations. Tip-induced voltage pulses firstly result in the formation of a diradical species via successive homolytic fission of two C-Br bonds in the naphthyl groups, which are subsequently transformed into chiral dehydroazulene moieties.

Control of Molecular Orbital Ordering Using a van der Waals Monolayer Ferroelectric.

2D ferroelectric materials provide a promising platform for the electrical control of quantum states. In particular, due to their 2D nature, they are suitable for influencing the quantum states of deposited molecules via the proximity effect. Here, electrically controllable molecular states in phthalocyanine molecules adsorbed on monolayer ferroelectric material SnTe are reported.

On-surface synthesis of disilabenzene-bridged covalent organic frameworks.

Substituting carbon with silicon in organic molecules and materials has long been an attractive way to modify their electronic structure and properties. Silicon-doped graphene-based materials are known to exhibit exotic properties, yet conjugated organic materials with atomically precise Si substitution have remained difficult to prepare. Here we present the on-surface synthesis of one- and two-dimensional covalent organic frameworks whose backbones contain 1,4-disilabenzene (CSi) linkers.

Rediscovery of the social wasp Mischocyttarus (Kappa) tapuya Schulz, with description of the female, larva and nest (Vespidae, Polistinae).

Mischocyttarus tapuya was originally described from a single male specimen collected in a forest near Belm, state of Par, Brazil, in the year of 1893, and had never been found again. We recently collected a colony of this species in an urban forest locality near Belm, and here describe the previously unknown female, mature larva, and nest of this social wasp.

Two-Dimensional Metal-Organic Framework on Superconducting NbSe.

The combination of two-dimensional (2D) materials into vertical heterostructures has emerged as a promising path to designer quantum materials with exotic properties. Here, we extend this concept from inorganic 2D materials to 2D metal-organic frameworks (MOFs) that offer additional flexibility in realizing designer heterostructures. We successfully fabricate a monolayer 2D Cu-dicyanoanthracene MOF on a 2D van der Waals NbSe superconducting substrate.

Electronic and Magnetic Characterization of Epitaxial CrBr Monolayers on a Superconducting Substrate.

The ability to imprint a given material property to another through a proximity effect in layered 2D materials has opened the way to the creation of designer materials. Here, molecular-beam epitaxy is used for direct synthesis of a superconductor-ferromagnet heterostructure by combining superconducting niobium diselenide (NbSe ) with the monolayer ferromagnetic chromium tribromide (CrBr ). Using different characterization techniques and density-functional theory calculations, it is confirmed that the CrBr monolayer retains its ferromagnetic ordering with a magnetocrystalline anisotropy favoring an out-of-plane spin orientation.

Topological superconductivity in a van der Waals heterostructure.

Exotic states such as topological insulators, superconductors and quantum spin liquids are often challenging or impossible to create in a single material. For example, it is unclear whether topological superconductivity, which has been suggested to be a key ingredient for topological quantum computing, exists in any naturally occurring material. The problem can be circumvented by deliberately selecting the combination of materials in heterostructures so that the desired physics emerges from interactions between the different components.

Taxonomic revision of the P. chartergoides species-group of the genus Protopolybia Ducke, 1905 (Hymenoptera: Vespidae, Polistinae).

A taxonomic revision of the Protopolybia chartergoides species-group was undertaken. Protopolybia isthmensis (Richards) stat. nov.

Amazon Sediment Transport and Accumulation Along the Continuum of Mixed Fluvial and Marine Processes.

Sediment transfer from land to ocean begins in coastal settings and, for large rivers such as the Amazon, has dramatic impacts over thousands of kilometers covering diverse environmental conditions. In the relatively natural Amazon tidal river, combinations of fluvial and marine processes transition toward the ocean, affecting the transport and accumulation of sediment in floodplains and tributary mouths. The enormous discharge of Amazon fresh water causes estuarine processes to occur on the continental shelf, where much sediment accumulation creates a large clinoform structure and where additional sediment accumulates along its shoreward boundary in tidal flats and mangrove forests.

Taxonomic revision of the Protopolybia picteti-emortualis species-group (Richards, 1978), with descriptions of two new species (Hymenoptera: Vespidae, Polistinae).

A taxonomic revision of the Protopolybia picteti-emortualis species-group now demonstrates that this group is possibly the largest in Protopolybia, comprising 15 species: P. eldinaris sp. nov.

Revision of the species-group of Mischocyttarus (Omega) filiformis (de Saussure 1854), with description of three new species (Hymenoptera, Vespidae).

A taxonomic revision of the species-group related to M. filiformis (Saussure 1854) is presented along with an identification key to species. After Richards (1978) and following the rearrangement of the subgenus Omega de Saussure by Silveira (2008), the species-group considered herein included three species in addition to M.

Update to the knowledge of the social wasps of the Brazilian state of Amapá based on the vespid collection of the Amapá Research Institute (IEPA) (Hymenoptera, Vespidae, Polistinae).

Information is presented concerning specimen records of polistine social wasps in the state of Amapá, Brazil, in the years from 1904 to 2016, mainly coming from the IEPA and MPEG collections. Spatial distribution of records and of the total collecting effort were analyzed with respect to general landscape aspects of the region, such as vegetation types, hydrography, road infrastructure and the state network of conservation unities. The number of social wasp species registered for Amapá is now 144, with 17 new records of species for the Guiana Shield, and nine species not yet described.

Interplay between magnetic, metal/insulator and topological phases in Hg Mn Te alloys: prediction of a ferromagnetic Weyl semimetal at x = 0.25.

We report a theoretical investigation of magnetic, electronic, and topological properties of Hg Mn Te alloys. We consider periodic structures with Mn concentrations as x  =  0, 0.25, 0.

Dynamics of aggregated states resolved by gated fluorescence in films of room temperature phosphorescent emitters.

Phenazine derivative molecules were studied using steady state and time resolved fluorescence techniques and demonstrated to lead to strong formation of aggregated species, identified as dimers by time dependent density functional theory calculations. Blended films in a matrix of Zeonex®, produced at different concentrations, showed different contributions of dimer and monomer emissions in a prompt time frame, e.g.

Optical absorption in complexes of abasic DNA with noble-metal nanoclusters by first principles calculations.

Abasic sites (AP site) in a DNA duplex have been experimentally used to produce fluorescent Ag nanoclusters (NC) with a small number of atoms (n ≤ 6). These AP-DNA:NC complexes act as biological makers that help to locate genes associated with diseases related to single nucleotide polymorphisms (SNP), for example. Abasic sites are the most common SNP genetic variation, and their detection may help predict a host of genetically determined diseases.

Historical records of orchid bees (Apidae: Euglossini) in Belém Endemism Center: species list of 92 years sampling.

The distribution of most species occurs in delimited regions with unique characteristics called "centers of endemism". In Eastern Amazon is located the Belém Endemism Center (BEC), one of the most intensely deforested in Brazilian Amazon. Here, we show information about orchid bee assemblages based on historical records from entomological collections.

Taxonomic revision of the Protopolybia sedula species-group (Hymenoptera, Vespidae, Polistinae), with an new identification key to species.

A taxonomic review of the P. sedula species-group is presented. New diagnostic characters are described and all species redescribed.