Quantum-confined single photon emission at room temperature from SiC tetrapods

Controlled engineering of isolated solid state quantum systems is one of the most prominent goals in modern nanotechnology. In this letter we demonstrate a previously unknown quantum system namely silicon carbide tetrapods. The tetrapods have a cubic polytype core (3C) and hexagonal polytype legs (4H)-a geometry that creates spontaneous polarization within a single tetrapod. Modeling of the tetrapod structures predicts that a bound exciton should exist at the 3C-4H interface. The simulations are confirmed by the observation of fully polarized and narrowband single photon emission from the tetrapods at room temperature. The single photon emission provides important insights into understanding the quantum confinement effects in non-spherical nanostructures. Our results pave the way to a new class of crystal phase nanomaterials that exhibit single photon emission at room temperature and therefore are suitable for sensing, quantum information and nanophotonics. © 2014 the Partner Organisations

SCHOOL PROBLEMS IN THE EDUCATION AND DEVELOPMENT OF GIFTED CHILDREN: PSYCHOLOGICAL ASPECT

Purpose of the Study: The urgency of the problem under investigation is because, the issue of gifted students’ education is one of the most difficult and interesting aspects of contemporary pedagogy. The purpose of the article is to identify the psychological characteristics of the gifted students’ development. In this article, the school difficulties of gifted students are revealed and the causes of internal and external nature are analyzed. Methodology: The leading approach to the study of this problem is a method of a theoretical analysis and synthesis of social, political, and psycho-pedagogical literature. Results: The main result of the study is a theoretical analysis of the relationship between learning and the development of gifted children and their psychological characteristics. Application:The materials of the article can be useful for teachers, students, and a wide range of readers interested in the problems of gifted students’ education. The authors pay special attention to the social and emotional consequences, which can be rather destructive if appropriate assistance is not provided by teachers, psychologists, and parents

SCHOOL PROBLEMS IN THE EDUCATION AND DEVELOPMENT OF GIFTED CHILDREN: PSYCHOLOGICAL ASPECT

Purpose of the Study: The urgency of the problem under investigation is due to the fact that the issue of gifted students’ education is one of the most difficult and interesting aspects of contemporary pedagogy. The purpose of the article is to identify the psychological characteristics of the gifted students’ development. In this article, the school difficulties of gifted students are revealed and the causes of internal and external nature are analyzed. The authors pay special attention to the social and emotional consequences, which can be rather destructive if appropriate assistance is not provided by teachers, psychologists, and parents. Methodology: The leading approach to the study of this problem is a method of theoretical analysis and synthesis of social, political and psycho-pedagogical literature. Results: The main result of the study is a theoretical analysis of the relationship between learning and the development of gifted children and their psychological characteristics. Application: The materials of the article can be useful for teachers, students and a wide range of readers interested in the problems of gifted students’ education

Characterization of the nitrogen split interstitial defect in wurtzite aluminum nitride using density functional theory

We carried out Heyd-Scuseria-Ernzerhof hybrid density functional theory plane wave supercell calculations in wurtzite aluminum nitride in order to characterize the geometry, formation energies, transition levels and hyperfine tensors of the nitrogen split interstitial defect. The calculated hyperfine tensors may provide useful fingerprint of this defect for electron paramagnetic resonance measurement.Comment: 5 pages, 3 figure

Vacancy-related color centers in two-dimensional silicon carbide monolayers

We examine vacancy defects in two-dimensional silicon carbide (2D-SiC) using density functional theory in order to explore their magneto-optical properties and their potential in quantum technologies. The defects include the silicon-vacancy (V$_{\text{Si}}$) and two antisite-vacancy pairs (V$_{\text{C}}$-C$_{\text{Si}}$ and V$_{\text{Si}}$-C$_{\text{Si}}$). We determine the characteristic hyperfine tensors and the fluorescence spectrum that are the key fingerprints of silicon-vacancy-related paramagnetic color centers in 2D-SiC and may be observed in electron paramagnetic resonance and photoluminescence experiments. In particular, we show that the V$_{\text{C}}$-C$_{\text{Si}}^-$ defect is promising candidate for a single-photon quantum emitter and qubit

Photo induced ionization dynamics of the nitrogen vacancy defect in diamond investigated by single shot charge state detection

The nitrogen-vacancy centre (NV) has drawn much attention for over a decade, yet detailed knowledge of the photophysics needs to be established. Under typical conditions, the NV can have two stable charge states, negative (NV-) or neutral (NV0), with photo induced interconversion of these two states. Here, we present detailed studies of the ionization dynamics of single NV centres in bulk diamond at room temperature during illumination in dependence of the excitation wavelength and power. We apply a recent method which allows us to directly measure the charge state of a single NV centre, and observe its temporal evolution. Results of this work are the steady state NV- population, which was found to be always < 75% for 450 to 610 nm excitation wavelength, the relative absorption cross-section of NV- for 540 to 610 nm, and the energy of the NV- ground state of 2.6 eV below the conduction band. These results will help to further understand the photo-physics of the NV centre.Comment: 9 pages, 7 figure

Engineering chromium related single photon emitters in single crystal diamond

Color centers in diamond as single photon emitters, are leading candidates for future quantum devices due to their room temperature operation and photostability. The recently discovered chromium related centers are particularly attractive since they possess narrow bandwidth emission and a very short lifetime. In this paper we investigate the fabrication methodologies to engineer these centers in monolithic diamond. We show that the emitters can be successfully fabricated by ion implantation of chromium in conjunction with oxygen or sulfur. Furthermore, our results indicate that the background nitrogen concentration is an important parameter, which governs the probability of success to generate these centers.Comment: 14 pages, 5 figure

Microstrip-fed 3D-printed H-sectorial horn phased array

A 3D-printed phased array consisting of four H-Sectorial horn antennas of 200 g weight with an ultra-wideband rectangular-waveguide-to-microstrip-line transition operating over the whole LMDS and K bands (24.25–29.5 GHz) is presented. The transition is based on exciting three overlapped transversal patches that radiate into the waveguide. The transition provides very low insertion losses, ranging from 0.30 dB to 0.67 dB over the whole band of operation (23.5–30.4 GHz). The measured fractional bandwidth of the phased array including the transition was 20.8% (24.75–30.3 GHz). The antenna was measured for six different scanning angles corresponding to six different progressive phases α, ranging from 0° to 140° at the central frequency band of operation of 26.5 GHz. The maximum gain was found in the broadside direction α = 0°, with 15.2 dB and efficiency η = 78.5%, while the minimum was found for α = 140°, with 13.7 dB and η = 91.2%.This work was supported by MINISTERIO DE CIENCIA, INNOVACIÓN Y UNIVERSIDADES: PID2019-107885GB-C31/AEI/10.13039/501100011033 and DI-2020.Peer ReviewedPostprint (published version