1,721,010 research outputs found
X-ray absorption spectroscopy study of atomic structure of epitaxial ErSi1.7(0001) on Si(111)
No full textSymmetry of the Itinerant 3d9 Ligand Hole Induced By Doping In High-tc Superconductors By Polarized Cu L3 Xas
No full textAn extensive study of electronic structure of YBa2Cu3O∼7vhas been carried out by means of X-ray spectroscopy. Polarized Cu L3 X-ray absorption spectra of single crystals have been measured and compared with the analogous spectra of polycrystalline samples with different oxygen content. From this analysis we have found that the electronic holes ∗ are associated with the d hole in the Cu 3d3z2-r2 orbital in the 3d9∗ configuration
ON THE ORBITAL ANGULAR-MOMENTUM OF CU 3D HOLES IN HIGH-TC-SUPERCONDUCTORS - IS A CU 3D3Z2-R2 BIPOLARON THE SUPERCONDUCTING PAIR
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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
Correlation between mixing of Cu d orbitals and Tc determined by polarized Cu L3 XAS: Experimental evidence for pairing mediated by d-d excitations
No full textEvidence For 3d9-ligand Hole Induced By Doping In Bi-sr-ca-cu-o and Tl-ca-ba-cu-o
No full textIn this work an investigation of Cu L3 x-ray absorption spectra XAS of the new high-Tc
compounds Bi-Sr-Ca-Cu-0 and Tl-Ca-Ba-Cu-0 is presented. The measured spectra give experimental
evidence that the states induced by cation doping of the copper oxides have the 3d9L (where the & indicates
a hole in the ligand orbital) configuration. Moreover the weight of these states has been found to be
correlated with the different critical temperatures. This is the same behaviour previously found in the case
of superconducting compounds Y-Ba-Cu-0 and Lu-Sr-Cu-0
Symmetry of the 3d9 Ligand Hole Induced By Doping In Yba2cu3o7-delta
No full textPolarized Cu L3-edge x-ray absorption spectra of a single crystal of YBa2Cu3O6.8 have been measured to determine the symmetry of the orbital of the electronic holes induced by doping. The states induced by doping in YBa2Cu3O7-δ (0<δ<~0.5) have been found to be ligand holes L*, giving the 3d9L* configuration, and their weight is correlated with Tc. The polarization dependence shows that the hole L*, induced by doping, is found to be mainly in the Cu-O orbital oriented along the c axis involving the O 2pz orbital of & orbitals. This result indicates the important role of BaO layers and shows that theories of high-Tc superconductivity have to take account of a second band with different symmetry, beyond the single band (the two-dimensional band & and O 2px,2py orbitals in the a-b plane of the CuO2 layers) usually considered in models of the electronic structure of high-Tc superconductors
High resolution polarized Cu L3 XAS of high temperature superconductors: correlations between the symmetry of d holes and the critical temperature
No full textVariations 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
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