4,912 research outputs found

    The thermal Hall effect of spin excitations in a Kagome magnet

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    At low temperatures, the thermal conductivity of spin excitations in a magnetic insulator can exceed that of phonons. However, because they are charge neutral, the spin waves are not expected to display a thermal Hall effect in a magnetic field. Recently, this semiclassical notion has been upended in quantum magnets in which the spin texture has a finite chirality. In the Kagome lattice, the chiral term generates a Berry curvature. This results in a thermal Hall conductivity κxy\kappa_{xy} that is topological in origin. Here we report observation of a large κxy\kappa_{xy} in the Kagome magnet Cu(1-3, bdc) which orders magnetically at 1.8 K. The observed κxy\kappa_{xy} undergoes a remarkable sign-reversal with changes in temperature or magnetic field, associated with sign alternation of the Chern flux between magnon bands. We show that thermal Hall experiments probe incisively the effect of Berry curvature on heat transport.Comment: 6 pages, 3 figure

    Integrated Freestanding Single-Crystal Silicon Nanowires: Conductivity and Surface Treatment

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    Integrated freestanding single-crystal silicon nanowires with typical dimension of 100 nm × 100 nm × 5 µm are fabricated by conventional 1:1 optical lithography and wet chemical silicon etching. The fabrication procedure can lead to wafer-scale integration of silicon nanowires in arrays. The measured electrical transport characteristics of the silicon nanowires covered with/without SiO2 support a model of Fermi level pinning near the conduction band. The I–V curves of the nanowires reveal a current carrier polarity reversal depending on Si–SiO2 and Si–H bonds on the nanowire surface

    Illicit Drugs: Should they be legalized? Can technology and regulation make them safer?

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    For many years America has been the leading force in substance prohibition. Many countries blindly follow the USA in an attempt to earn their respect. As a result, very few countries actually know what uses these illicit substances have; before it ever reached the hands of the right people, the wrong people take it, use it incorrectly, and leave a bad name on that substance forever. If people could slander a substance, America would end up being found the main conspirator in the slanderous lies and misconceptions! This study has been done in an attempt to clear the name of most illicit drugs to pave a path towards legalization. This path will require tumultuous amounts of research, experimentation, and education. Once that path is complete, a marked path should begin continuing education to the public and beginning regulation and sale of all illicit drugs.Kayla SiddellHonors DiplomaHonors CollegeCunningham Memorial Library, Terre Haute, Indiana State UniversityUndergraduateTitle from document title page. Document formatted into pages: 28
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