Spin-polarized transport in a quasi-1D wire with Rashba dots

A numerical study on spin-polarized transport properties in a quasi-one-dimensional wire with Rashba quantum dots is presented. The ballistic spin transmission probability and spin density profiles are obtained using the quantum transmitting boundary method. The Fano-Rashba effect on the spin transmission is analyzed as a function of the Rashba spin-orbit coupling strength for single dot and double dot systems. The spin density profiles show the localized states that contribute to the backscattering and spin-flip processes in the Rashba dots. The results enlighten us on the Fano-Rashba effect caused by local Rashba spin-orbit coupling and provide concrete ideas for modeling a system with spin-polarized transport for future applications

Stabilization of halide perovskites with silicon compounds for optoelectronic, catalytic, and bioimaging applications

Silicon belongs to group 14 elements along with carbon, germanium, tin, and lead in the periodic table. Similar to carbon, silicon is capable of forming a wide range of stable compounds, including silicon hydrides, organosilicons, silicic acids, silicon oxides, and silicone polymers. These materials have been used extensively in optoelectronic devices, sensing, catalysis, and biomedical applications. In recent years, silicon compounds have also been shown to be suitable for stabilizing delicate halide perovskite structures. These composite materials are now receiving a lot of interest for their potential use in various real‐world applications. Despite exhibiting outstanding performance in various optoelectronic devices, halide perovskites are susceptible to breakdown in the presence of moisture, oxygen, heat, and UV light. Silicon compounds are thought to be excellent materials for improving both halide perovskite stability and the performance of perovskite‐based optoelectronic devices. In this work, a wide range of silicon compounds that have been used in halide perovskite research and their applications in various fields are discussed. The interfacial stability, structure–property correlations, and various application aspects of perovskite and silicon compounds are also analyzed at the molecular level. This study also explores the developments, difficulties, and potential future directions associated with the synthesis and application of perovskite‐silicon compounds. imag

Investigation of electron irradiation-induced magnetism in layered MoS2 single crystals

By using higher acceleration energies than the displacement energy of Mo atoms, the electron irradiation on the layered MoS2 single crystals is found to be an effective and simple method to induce the diamagnetic to ferromagnetic phase transition persisting up to room temperature. The easy axis can be controllable by regulating the electron dose and the acceleration energy. The ferromagnetic states are largely attributed to the strain around the vacancies.clos

Dataset on electro-optically tunable smart-supercapacitors based on oxygen-excess nanograin tungsten oxide thin film

The dataset presented here is related to the research article entitled ???Highly Efficient Electro-optically Tunable Smart-supercapacitors Using an Oxygen-excess Nanograin Tungsten Oxide Thin Film??? (Akbar et al., 2017) [9] where we have presented a nanograin WO3 film as a bifunctional electrode for smart supercapacitor devices. In this article we provide additional information concerning nanograin tungsten oxide thin films such as atomic force microscopy, Raman spectroscopy, and X-ray diffraction spectroscopy. Moreover, their electrochemical properties such as cyclic voltammetry, electrochemical supercapacitor properties, and electrochromic properties including coloration efficiency, optical modulation and electrochemical impedance spectroscopy are presented

Annealing effects of morphology and luminescence properties of pulsed laser-deposited SrAl2O4: Eu, Dy thin films on sapphire (0001) surfaces

The current work reports on the effect of annealing temperatures on the morphology and photoluminescence properties of SrAl2O4: Eu, Dy thin films on sapphire (0001) substrates fabricated by pulsed laser deposition technique. Scanning electronic microscopy and atomic force microscopy were used to investigate the thickness, surface topography, and the morphology of the films. The film deposited using a higher annealing temperature was packed with a uniform layer of larger particle size grains. In addition, the surface of this film was shown to be relatively rougher than that without annealing treatment. An intense green emission, which is attributed to the 5d-4f transition of Eu2 + was observed at about 520 nm from the films with annealing treatment. The effects of annealing treatment on the morphology, topography, and photoluminescence properties are discussed in detail

Acetal-Based Functional Epoxide Monomers: Polymerizations and Applications

Protecting group chemistry is essential for various organic transformation and polymerization processes. In particular, conventional anionic ring-opening polymerization (AROP) often requires proper protecting group chemistry because it is typically incompatible with most functional groups due to the highly basic and nucleophilic conditions. In this context, many functional epoxide monomers with proper protecting groups are developed, including the acetal group as a representative example. Since the early introduction of ethoxyethyl glycidyl ether, there is significant development of acetal-based monomers in the polyethers. These monomers are now utilized not only as protecting groups for hydroxyl groups under AROP conditions but also as pH-responsive moieties for biomedical applications, further expanding their utility in the use of functionalized polyethers. Recent progress in this field is outlined from their synthesis, polymerization, and biomedical applications

Correlation between lateral size and gas sensing performance of MoSe2 nanosheets

We demonstrate a facile synthetic method to prepare lateral size controlled molybdenum diselenide (MoSe2) nanosheets using liquid phase exfoliated few-layer MoSe2 nanosheets as a starting material. By precisely controlling the centrifugation condition, preparation of MoSe2 nanosheets with a narrow size distribution ranging from several hundred nanometers to several micrometers could be realized. The accurate size control of MoSe2 nanosheets offers us a great opportunity to examine the size dependent sensing properties. The sensing test results demonstrate that the MoSe2 nanosheets provide competitive advantages compared with conventional graphene based sensors. A tradeoff phenomenon on sensing response and recovery as the lateral size of MoSe2 nanosheets varies is observed. First principles calculations reveal that the ratio of edge-surface sites is responsible for this phenomenon. The correlation between the lateral size and gas sensing performance of MoSe2 nanosheets is established

Cell reprogramming into the pluripotent state using graphene based substrates

Graphene has been attracting considerable interest in the field of biomedical engineering because graphene and its derivatives are considered to be ideal platforms for supporting cell growth and differentiation. Here we report that graphene promotes the reprogramming of mouse somatic fibroblasts into induced pluripotent stem cells (iPSCs). We constructed a layer of graphene film on a glass substrate and characterized it as a monolayer using Raman spectroscopy. We found that the graphene substrate significantly improved cellular reprogramming efficiency by inducing mesenchymal-to-epithelial-transition (MET) which is known to affect H3K4me3 levels. Thus, our results reveal that a graphene substrate directly regulates dynamic epigenetic changes associated with reprogramming, providing an efficient tool for epigenetic pluripotent reprogramming.close3

Electronic structure of the Au-intercalated graphene/Ni(111) surface

We report the electronic structure of the Au-intercalated graphene/Ni(111) surface using angle-resolved photoemission spectroscopy and low energy electron diffraction. The graphene/Ni(111) shows no Dirac cone near the Fermi level and a relatively broad C is core level spectrum probably due to the broken sublattice symmetry in the graphene on the Ni(111) substrate. When Au atoms are intercalated between them, the characteristic Dirac cone is completely recovered near the Fermi level and the C 1s spectrum becomes sharper with the appearance of a 10 x 10 superstructure. The fully Au-intercalated graphene/Ni(111) surface shows a p-type character with a hole pocket of similar to 0.034 angstrom(-1) diameter at the Fermi level. When the surface is doped with Na and K, a clear energy gap of similar to 0.4 eV is visible irrespective of alkali metal

Exciton dynamics in monolayer graphene grown on a Cu(111) surface

We have characterized the carrier dynamics of the excitonic emission emerging from a monolayer of graphene grown on a Cu(111) surface. Excitonic emission from the graphene, with strong and sharp peaks both with a full-width at half-maximum of 2.7 meV, was observed near similar to 3.16 and similar to 3.18 eV at 4.2 K. The carrier recombination parameters were studied by measuring both temperature-dependent and time-resolved photoluminescence. The intensity variation with temperature of these two peaks shows an opposing trend. The time-resolved emission was modelled using coupled differential equations and the decay time was found to be dominated by carrier trapping and Auger recombination as the temperature increased