Intrinsic Half-metallicity in Edge Fluorinated Armchair Boron Nitride Nanoribbons

We predict intrinsic half-metallicity in armchair boron nitride nanoribbons (ABNNRs) via edge fluorination. The stability, electronic and magnetic properties of bare and edge fluorinated ABNNRs have been systematically analyzed by means of first-principles calculations within the local spin-density approximation (LSDA). The ribbons whose only edge-B atoms passivated with F atoms (i.e., edge-N atoms are un-passivated), regardless of width, are found half-metallic with a half-metal gap of 0.3 eV. A 100 \% spin polarized charge transport across the Fermi level is expected for such ribbons as the spin polarized states are $\sim$0.4 eV more stable than the spin un-polarized states and only single-spin conducting channels are present across the Fermi level owing to the gigantic spin splitting. The existence of half-metallicity is attributed to the localization of electronic charge at bare edge-N atoms as revealed from the analysis of Bloch states and projected density of states (PDOS).The sufficiently large half-metal gap (0.3 eV) with huge difference in the energies ($\sim$ 0.4 eV) of spin polarized and spin compensated states projects these half-metallic ABNNRs as potential candidate for spintronics applications.Comment: Error in Typing in older versio

Investigation of work function and chemical composition of thin films of borides and nitrides

Thin films of various borides, nitrides, and barium fluorides were tentatively deposited by pulsed laser deposition and by magnetron sputtering in order to develop the components of thermionic-photovoltaic devices for the high-temperature thermal to electrical conversion by solid state. To improve the device performance, the materials characterized by a low work function were selected. In the present work, the chemical composition and work function of obtained films were investigated by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy techniques. The values of work function were determined from the cut-off in the He I valence band spectra. Different films were compared and estimated on the basis of X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy results

Interplay between Phonon Confinement and Fano Effect on Raman line shape for semiconductor nanostructures: Analytical study

Theoretical Raman line shape functions have been studied to take care of quantum confinement effect and Fano effect individually and jointly. The characteristics of various Raman line shapes have been studied in terms of the broadening and asymmetry of Raman line shapes. It is shown that the asymmetry in the Raman line-shape function caused by these two effects individually does not add linearly to give asymmetry of line-shape generated by considering the combined effect. This indicates existence of interplay between the two effects. The origin of interplay lies in the fact that Fano effect itself depends on quantum confinement effect and in turn provides an asymmetry. This can not be explained by considering the two effects contribution independent of each other.Comment: 10 Page

¬Peningkatan Pemahaman Konsep Tekanan Hidrostatis dan Hukum Archimedes Siswa SMP¬ melalui Pembelajaran Discovery

This study aims to increase the students\u27 comprehension of the concept of hydrostatic pressure and the law of Archimedes through discovery learning. The subjects of the study were VIII-A SMPK Citra Bangsa Kupang, Province of East Nusa Tenggara in the academic year 2016/2017. The data of this study consisted of quantitative and qualitative data. The instruments used in the study were pretest and posttest in the form of reasoned multiple choice. The result of data analysis of concept comprehension showed that the posttest average score was 83.33 and it was greater than the pretest score that achieved 46.66. The calculation of d-effect size was 2.73 (very high category) and N-gain was 0.69 (medium category). Thus, it is concluded that the discovery learning model has a positive impact on the improvement of concept comprehension.Penelitian ini bertujuan meningkatkan pemahaman konsep tekanan hidrostatis dan hokum Archimedes siswa melalui pembelajaran discovery. Subjek penelitian adalah siswa kelas VIIIA SMPK Citra Bangsa Kupang, Provinsi Nusa Tenggara Timur tahun pelajaran 2016/2017. Data penelitian terdiri atas data kuantitatif dan kualitatif. Instrumen yang digunakan dalam penelitian yaitu pretes dan postes dalam bentuk pilihan ganda beralasan. Hasil analisis data pemahaman konsep menunjukkan bahwa skor rata-rata postes 83,33 lebih besar daripada skor rata-rata pretes 46,66. Perhitungan d-effect size sebesar 2,73 (kategori sangat tinggi) dan N-gain sebesar 0,69 (kategori sedang). Maka, disimpulkan bahwa model discovery learning memberikan dampak positif terhadap peningkatan pemahaman konsep