1,720,958 research outputs found
Unconventional localization of electrons inside of a nematic electronic phase: FeSe thin flakes magnetotransport
No full textThese are magnetotransport data on devices made of thin flakes of FeSe. The data were collected in a cryostat in magnetic fields as a function of temperature and at fixed temperatures the magnetic field was ramped to the maximum value both in the CFAS lab in Oxford and at the HMFL in Nijmegen. The magnetotransport data were collected using Hall bar geometries or a spider geometry. The data contain mainly ASCII files and the PDF figures are provided. This work is part of the publication "Unconventional localization of electrons inside of a nematic electronic phase" which will appear in PNAS 2022
Strain-tuning the electronic structure of iron chalogenide superconductors
No full textUnconventional superconductors hold promise for high-temperature superconductivity, but their pairing mechanism remains uncertain. A key approach to understanding this is studying the normal state phases from which superconductivity emerges. In iron chalcogenide superconductors, this phase is the nematic electronic phase, and this thesis investigates its influence on the electronic structure using angle-resolved photoemission spectroscopy (ARPES). Using low-energy models I can quantify the experimental band dispersion and identify the orbital character. I further compliment these measurements with density functional theory calculations.
Initially, I examine the electronic structure of nematic FeSe1−xTex. From increasing the Te concentration, I find the effective masses of each hole band to reduce for x < 0.3. However, beyond this I observe significant variations in the hole band of dxy orbital character. As Te concentration increases, this band shifts towards the Fermi level, correlating with an increase in its effective mass and an enhanced superconductivity. To explore how strain couples to the nematic order, I apply uniaxial strain to FeSe1−xSx and track the electronic spectral function. I quantify momentum dependent band splittings, orbital transmutation and an orbital dependent spectral weight transfer at hole pockets. These findings align well with other nematic systems, offering a comprehensive description of how the nematic phase distorts the electronic structure. Furthermore, I conduct temperature-dependent ARPES on three FeSe1−xSx systems under fixed symmetry-breaking strain. I observe significant temperature dependence within the spectral weight and band splittings at the hole pockets. In contrast, the band splittings at the electron pockets show a weaker temperature dependence, indicating they are driven predominantly by pure lattice distortion, rather than via the nematic order. Lastly, transport studies reveal no clear coupling between symmetry-breaking strain and superconductivity. Instead, I observe a linear strain dependence of the superconducting transition, where the trends agree with symmetry preserving pressure studies
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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