Nanoskyrmion engineering with spsp-electron materials: Sn monolayer on SiC(0001) surface

Materials with $sp$-magnetism demonstrate strongly nonlocal Coulomb interactions, which opens a way to probe correlations in the regimes not achievable in transition metal compounds. By the example of Sn monolayer on SiC(0001) surface, we show that such systems exhibit unusual but intriguing magnetic properties at the nanoscale. Physically, this is attributed to the presence of a significant ferromagnetic coupling, the so-called direct exchange, which fully compensates ubiquitous antiferromagnetic interactions of the superexchange origin. Having a nonlocal nature, the direct exchange was previously ignored because it cannot be captured within the conventional density functional methods and significantly challenges ground state models earlier proposed for Sn/SiC(0001). Furthermore, heavy adatoms induce strong spin-orbit coupling, which leads to a highly anisotropic form of the spin Hamiltonian, in which the Dzyaloshinskii-Moriya interaction is dominant. The latter is suggested to be responsible for the formation of a nanoskyrmion state at realistic magnetic fields and temperatures.Comment: 4 pages, supplemental materia

Effect of oxygen on the electrical conductivity of Pt-contacted α-Ga2O2/ε(κ)-Ga2O3 MSM structures on patterned sapphire substrates

Electrical conductivity and gas sensitivity of α-Ga2O2/ ε(κ)-Ga2O3 structures were measured for oxygen concentrations ranging from 2 % to 100 % and temperatures ranging from 25 °C to 220 °C. It was found that the oxygen sensitivity of the structures depended on the donor dopant concentration. The alpha -Ga _{2}O_{3}/arepsilon ( kappa )-Ga 2 O 3 structures doped with sim 1.5 imes 10^{17} cm −3 of Sn showed high sensitivity to O 2 in the temperature range from 180 °C to 220 °C and at the bias voltage below 7.5 V. This effect can be attributed to the chemisorption of oxygen molecules on the surface of structures, which reduces energy barriers between ε(κ)-Ga2O3 grains

Detection of Genomic Variation by Selection of a 9 Mb DNA Region and High Throughput Sequencing

Detection of the rare polymorphisms and causative mutations of genetic diseases in a targeted genomic area has become a major goal in order to understand genomic and phenotypic variability. We have interrogated repeat-masked regions of 8.9 Mb on human chromosomes 21 (7.8 Mb) and 7 (1.1 Mb) from an individual from the International HapMap Project (NA12872). We have optimized a method of genomic selection for high throughput sequencing. Microarray-based selection and sequencing resulted in 260-fold enrichment, with 41% of reads mapping to the target region. 83% of SNPs in the targeted region had at least 4-fold sequence coverage and 54% at least 15-fold. When assaying HapMap SNPs in NA12872, our sequence genotypes are 91.3% concordant in regions with coverage≥4-fold, and 97.9% concordant in regions with coverage≥15-fold. About 81% of the SNPs recovered with both thresholds are listed in dbSNP. We observed that regions with low sequence coverage occur in close proximity to low-complexity DNA. Validation experiments using Sanger sequencing were performed for 46 SNPs with 15-20 fold coverage, with a confirmation rate of 96%, suggesting that DNA selection provides an accurate and cost-effective method for identifying rare genomic variants

Early History of Mammals Is Elucidated with the ENCODE Multiple Species Sequencing Data

Understanding the early evolution of placental mammals is one of the most challenging issues in mammalian phylogeny. Here, we addressed this question by using the sequence data of the ENCODE consortium, which include 1% of mammalian genomes in 18 species belonging to all main mammalian lineages. Phylogenetic reconstructions based on an unprecedented amount of coding sequences taken from 218 genes resulted in a highly supported tree placing the root of Placentalia between Afrotheria and Exafroplacentalia (Afrotheria hypothesis). This topology was validated by the phylogenetic analysis of a new class of genomic phylogenetic markers, the conserved noncoding sequences. Applying the tests of alternative topologies on the coding sequence dataset resulted in the rejection of the Atlantogenata hypothesis (Xenarthra grouping with Afrotheria), while this test rejected the second alternative scenario, the Epitheria hypothesis (Xenarthra at the base), when using the noncoding sequence dataset. Thus, the two datasets support the Afrotheria hypothesis; however, none can reject both of the remaining topological alternatives

Low-resistivity gas sensors based on the In2O3-Ga2O3 mixed compounds films

The effect of H2, NH3, CO, CH4, O2 and NO2 on the electroconductive properties of the In2O3-Ga2O3 mixed compounds films obtained by the halide vapor phase epitaxy was studied. In the temperature range of 150–550 °C In2O3-Ga2O3 films are characterized by high responses, high speed of operation when exposed to H2, NH3, CO and O2. A qualitative mechanism of gas sensitivity for the In2O3-Ga2O3 mixed compounds films to gases was proposed. The gas-sensitive characteristics of In2O3, κ(ε)-Ga2O3 and In2O3-Ga2O3 films were compared. The advantage of the In2O3-Ga2O3 mixed compounds films compared with Ga2O3 and In2O3 films is a low base electrical resistivity with a relatively high gas sensitivity

HVPE growth of corundum-structured α-Ga2O3 on sapphire substrates with α-Cr2O3 buffer layer

Gallium oxide films were grown by HVPE on (0001) sapphire substrates with and without α-Cr2O3 buffer produced by RF magnetron sputtering. Deposition on bare sapphire substrates resulted in a mixture of α-Ga2O3 and ε-Ga2O3 phases with a dislocation density of about 2∙1010 cm-2. The insertion of α-Cr2O3 buffer layers resulted in phase-pure α-Ga2O3 films and a fourfold reduction of the dislocation density to 5∙109 cm-2

Phylogenomics Reshuffles the Eukaryotic Supergroups

Background. Resolving the phylogenetic relationships between eukaryotes is an ongoing challenge of evolutionary biology. In recent years, the accumulation of molecular data led to a new evolutionary understanding, in which all eukaryotic diversity has been classified into five or six supergroups. Yet, the composition of these large assemblages and their relationships remain controversial. Methodology/Principle Findings. Here, we report the sequencing of expressed sequence tags (ESTs) for two species belonging to the supergroup Rhizaria and present the analysis of a unique dataset combining 29908 amino acid positions and an extensive taxa sampling made of 49 mainly unicellular species representative of all supergroups. Our results show a very robust relationship between Rhizaria and two main clades of the supergroup chromalveolates: stramenopiles and alveolates. We confirm the existence of consistent affinities between assemblages that were thought to belong to different supergroups of eukaryotes, thus not sharing a close evolutionary history. Conclusions. This well supported phylogeny has important consequences for our understanding of the evolutionary history of eukaryotes. In particular, it questions a single red algal origin of the chlorophyll-c containing plastids among the chromalveolates. We propose the abbreviated name ‘SAR’ (Stramenopiles+Alveolates+Rhizaria) to accommodate this new super assemblage of eukaryotes, which comprises the largest diversity of unicellular eukaryotes