1,720,971 research outputs found
Directional radiation of Babinet-inverted optical nanoantenna integrated with plasmonic waveguide
Get PDFWe present a Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide. Using an integrated nanoantenna, we can couple the plasmon guide mode in a metal-insulator-metal (MIM) structure into the resonant antenna feed directly. The resonantly excited feed slot then radiates to free space and generates a magnetic dipole-like far-field pattern. The coupling efficiency of the integrated nanoantenna is calculated as being approximately 19% using a three-dimensional finite-difference time-domain (3D FDTD) simulation. By adding an auxiliary groove structure along with the feed, the radiation direction can be controlled similar to an optical Yagi-Uda antenna. We also determine, both theoretically and experimentally, that groove depth plays a significant role to function groove structure as a reflector or a director. The demonstrated Babinet-inverted optical nanoantenna integrated with a plasmonic waveguide can be used as a plasmonic viaa in plasmonic nanocircuits1771sciescopu
Stretchable energy-harvesting tactile electronic skin capable of differentiating multiple mechanical stimuli modes
No full textThe first stretchable energy harvesting e-skin (EHES) that is able to detect, differentiate, and harvest a variety of mechanical stimuli, enabled by the stretchability of the device and a unique device architecture was reported. Using PDMS microstructuring in combination with an air gap, the researchers enabled pressure sensing from several pascals to tens of kilopascals. The device was capable of differentiating different tactile signals by measuring three different output signals (capacitance, resistance of the top and resistance of the bottom electrode). The capacitive design was important since the top and the bottom electrodes needed to be electrically isolated so that the measured change in film resistance was only due to the lateral straining of each film, not due to the electrical conduction between the top and bottom electrodes. Capacitive sensor design also enabled energy-harvesting functionality along with its sensing capability. envision that our energy-harvesting e-skin and the concepts introduced here can be utilized in the future to enable a fully self-sustainable skin-like devices with stretchability, multifunctional tactile sensing, and energy-harvesting capability
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim11451551sciescopu
Nanoscale manipulation of the Mott insulating state coupled to charge order in 1T-TaS2
Get PDFThe controllability over strongly correlated electronic states promises unique electronic devices. A recent example is an optically induced ultrafast switching device based on the transition between the correlated Mott insulating state and a metallic state of a transition metal dichalcogenide 1T-TaS2. However, the electronic switching has been challenging and the nature of the transition has been veiled. Here we demonstrate the nanoscale electronic manipulation of the Mott state of 1T-TaS2. The voltage pulse from a scanning tunnelling microscope switches the insulating phase locally into a metallic phase with irregularly textured domain walls in the charge density wave order inherent to this Mott state. The metallic state is revealed as a correlated phase, which is induced by the moderate reduction of electron correlation due to the charge density wave decoherence.131321sciescopu
Chiral solitons in a coupled double Peierls chain
No full textChiral edge states are the hallmark of two- and three-dimensional topological materials,
but their one-dimensional (1D) analog has not yet been found. We report that the 1D
topological edge states, solitons, of the charge density wave system of indium atomic
wires self-assembled on a silicon surface have chirality. The system is described by a
coupled double Peierls-dimerized atomic chain, where the interchain coupling induces
dynamical sublattice symmetry breaking. This changes its topological symmetry from
Z2 Z2 to Z4 and endows solitons with a chiral degree of freedom. Chiral solitons can
produce quantized charge transport across the chain that is topologically protected and
controllable by the soliton’s chirality. Individual right- and left-chiral solitons in indium
wires are directly identified by scanning tunneling microscopy.123201sciescopu
Switching chiral solitons for algebraic operation of topological quaternary digits
No full textChiral objects can be found throughout nature(1-4); in condensed matter chiral objects are often excited states protected by a system's topology. The use of chiral topological excitations to carry information has been demonstrated, where the information is robust against external perturbations(5,6). For instance, reading, writing, and transfer of binary information have been demonstrated with chiral topological excitations in magnetic systems, skyrmions(7-14), for spintronic devices(13-19). The next step is logic or algebraic operations of such topological bits(20-22). Here, we show experimentally the switching between chiral topological excitations or chiral solitons of different chirality in a one-dimensional electronic system with Z(4) topological symmetry(23,24). We found that a fast-moving achiral soliton merges with chiral solitons to switch their handedness. This can lead to the realization of algebraic operation of Z(4) topological charges(25). Chiral solitons could be a platform for storage and operation of robust topological multi-digit information.1172sciescopu
Emergence of Topological Superconductivity in Doped Topological Dirac Semimetals under Symmetry-Lowering Lattice Distortions
Get PDFRecently, unconventional superconductivity having a zero-bias conductance
peak is reported in doped topological Dirac semimetal (DSM) with lattice
distortion. Motivated by the experiments, we theoretically study the possible
symmetry-lowering lattice distortions and their effects on the emergence of
unconventional superconductivity in doped topological DSM. We find four types
of symmetry-lowering lattice distortions that reproduce the crystal symmetries
relevant to experiments from the group-theoretical analysis. Considering
inter-orbital and intra-orbital electron density-density interactions, we
calculate superconducting phase diagrams. We find that the lattice distortions
can induce unconventional superconductivity hosting gapless surface Andreev
bound states (SABS). Depending on the lattice distortions and superconducting
pairing interactions, the unconventional inversion-odd-parity superconductivity
can be either topological nodal superconductivity hosting a flat SABS or
topological crystalline superconductivity hosting a gapless SABS. Remarkably,
the lattice distortions increase the superconducting critical temperature,
which is consistent with the experiments. Our work opens a pathway to explore
and control pressure-induced topological superconductivity in doped topological
semimetals.Comment: 26 + 14 pages, 8 + 2 figure
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
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