2,367 research outputs found
Magnetism in 2D BNO and BSiN: polarized itinerant and local electrons
We use density functional theory based first-principles methods to study the
magnetism in a 2D hexagonal BN sheet induced by the different concentrations of
oxygen and silicon atoms substituting for nitrogen (O) and boron
(Si) respectively. We demonstrate the possible formation of three
distinct phases based on the magnetization energy calculated self-consistently
for the ferromagnetic (ME) and antiferromagnetic
(ME) states, i.e. the paramagnetic phase with
ME=ME, the ferromagnetic phase with
MEME and finally the polarized itinerant
electrons with finite ME but zero ME. While
the O system was found to exist in all three phases, no tendency
towards the formation of the polarized itinerant electrons was observed for the
Si system though the existence of the other two phases was
ascertained. The different behavior of these two systems is associated with the
diverse features in the magnetization energy as a function of the oxygen and
silicon concentrations. Finally, the robustness of the polarized itinerant
electron phase is also discussed with respect to the O substitute atom
distributions and the applied strains to the system.Comment: accepted by RP
Book Reviews
Reviews of How Race is Made in America: Immigration, Citizenship, and the Historical Power of Racial Scripts and Reframing the Latino Immigration Debate: Towards a Humanistic Paradig
Phonons of single quintuple Bi2Te3 and Bi2Se3 films and bulk materials
Phonons of single quintuple films of Bi2Te3 and Bi2Se3 and corresponding bulk materials are calculated in detail by MedeA (a trademark of Materials Design) and Vienna ab initio simulation package (VASP). The calculated results with and without spin-orbit couplings are compared, and the important roles that the spin-orbit coupling plays in these materials are discussed. A symmetry breaking caused by the anharmonic potentials around Bi atoms in the single quintuple films is identified and discussed. The observed Raman intensity features in Bi2Te3 and Bi2Se3 quintuple films are explained
Calculations of surface effects on phonon modes and Raman intensities of Ge quantum dots
Phonon modes and Raman intensities of Ge quantum dots (QDs) with two different types of surfaces, a free standing surface or a fixed surface, in a size range from five atoms to 7 nm in diameter, are calculated by using a microscopic valence force field model. The results are compared, and the effects of surfaces on phonon properties of QDs are investigated. It is found that phonon modes and Raman intensities of QDs with these two different types of surfaces have obvious differences which clearly reveal the effects of the surfaces of QDs. The calculated results agree with existing experimental observations. We expect that our calculations will stimulate more experimental measurements on phonon properties and Raman intensities of QDs
An exact single-agent task selection algorithm for the crowdsourced logistics
Agency for Science, Technology and Research (A*STAR); Fujitsu; National Research Foundation (NRF) Singapor
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