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Nov 2020 • International Conference on Ultrafast Phenomena, M3A. 1, 2020

Probing electron-phonon couplings in halide perovskites crystals by temperature-dependent ultrafast two-dimensional electronic spectroscopy

Xuan Trung Nguyen, Daniel Timmer, Yevgeny Rakita, David Cahen, Alexander Steinhoff, Frank Jahnke, Christoph Lienau, Antonietta De Sio

We track ultrafast charge carrier relaxation and the concurrent build-up of dynamical exciton screening on a 30-fs timescale, and probe strong electron-phonon couplings in halide perovskite crystals by temperature-dependent two-dimensional electronic spectroscopy.

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Nov 2020 • Univ. of Maryland, College Park, MD (United States), 2020

Protection layers for metal anodes

Alexander C Kozen, Marshall A Schroeder, Gary W Rubloff, Liangbing Hu, Malakhi Noked, Sang Bok Lee

A protection layer is formed on a highly-reactive substantially-pure metal anode to a thickness of between 1 nm and 200 nm, inclusive, using atomic layer deposition (ALD). The ALD protection layer allows the conduction of ions of the metal of the anode therethrough but suppresses electron transport therethrough. The ALD protection layer may also be effective to inhibit passage of air and/or water therethrough. The ALD protection layer can allow more relaxed purity requirements for subsequent battery assembly, electrolyte specifications, and/or cathode gas purity. Fabrication methods for the protection layers, protected metal anodes, and systems and devices incorporating such protected metal anodes are also disclosed herein.

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Oct 2020 • Scientific reports

Fibers-based temporal super-resolved imaging

Sagie Asraf, Moti Fridman, Zeev Zalevsky

In this paper we present a new technique for a fiber-based temporal super resolving system allowing to improve the resolution of a temporal imaging system. The proposed super resolving concept is based upon translating the field of view multiplexing method that is used to increase resolution in spatial imaging systems from the spatial domain to the temporal domain. In this paper, an optical realization of our proposed system is presented, using optical fibers and electro-optic modulators. In addition, we show how one can apply this method using low-rate electronics for the required modulation. We also show simulation results that demonstrate the high resolution accepted in our method compares to the basic temporal imaging system. Experimental results which demonstrate resolution improvement by a factor of 1.5 based on the proposed method are presented together with an additional experiment that shows the …

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Oct 2020 • Royal Society of Chemistry, 2020

New magnetically responsive polydicarbazole-magnetite nanoparticlesElectronic supplementary information (ESI) available: experimental details including analyses. See http://www …

Jean-Paul Lellouche, Nurit Perlman, Augustine Joseph, Senthil Govindaraji, Ludmila Buzhansky, Aline Yakir, Ian Bruce

Magnetically responsive COOH-polydicarbazole-magnetite nanocomposites have been prepared by chemical oxidation of three COOH-dicarbazole monomers 1 and 4â 5 in the presence of magnetite nanoparticles. These functionalized nanoparticles have been tested for DNA hybridization experiments.

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Oct 2020 • Scientific Reports

Author Correction: Generation and Manipulation of Superoscillatory Hotspots Using Virtual Fourier Filtering and CTF Shaping

Abhijit Sanjeev, Nadav Shabairou, Arrad Attar, Daniel Scherbaum, Yuval Kapellner, Moshe Sinvani, Zeev Zalevsky

The original version of this Article contained a typographical error in the spelling of the author Daniel Scherbaum, which was incorrectly given as Daniel Scheberbaum. This has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Information file.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author (s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not …

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Oct 2020

System and method for imaging with pinhole arrays

Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) 2014-02-06

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Oct 2020 • Scientific Reports

Nano polarimetry: enhanced AFM-NSOM triple-mode polarimeter tip

Matityahu Karelits, Zeev Zalevsky, Avi Karsenty

A novel application of a combined and enhanced NSOM-AFM tip-photodetector system resulted in a nanoscale Polarimeter, generated by four different holes, each sharing a different shape, and enabling that the four photonic readouts forming the tip will be the four Stokes coefficients, this in order to place the polarization state in the Poincare sphere. The new system has been built on standard Atomic Force Microscope (AFM) cantilever, in order to serve as a triple-mode scanning system, sharing complementary scanning topography, optical data analysis and polarization states. This new device, which has been designed and simulated using Comsol Multi-Physics software package, consists in a Platinum-Silicon drilled conical photodetector, sharing subwavelength apertures, and has been processed using advanced nanotechnology tools on a commercial silicon cantilever. After a comparison study of drilled …

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Oct 2020 • TRANSGENIC RESEARCH 29 (SUPPL 1), 9-9, 2020

Testis formation in XX individuals resulting from novel pathogenic variants in Wilms' tumor 1 (WT1) gene

Nitzan Gonen

Oct 2020 • 2020 Asia Communications and Photonics Conference (ACP) and International …, 2020

Surface Acoustic Wave Integrated-Photonic Radio-Frequency Filters with Arbitrary Complex Tap Coefficients

Dvir Munk, Moshe Katzman, Maayan Priel, Mirit Hen, Avi Zadok

Discrete time, integrated microwave photonic filters with narrow bandwidths are realized in standard silicon on insulator. Long delays are achieved using slow moving surface acoustic waves. The complex magnitude of each tap is chosen arbitrarily. © 2020 The Author(s)

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Oct 2020 • arXiv preprint arXiv:2010.06180

Selective Pumping of Localized States in a Disordered Active Medium

Bhupesh Kumar, Mélanie Lebental, Patrick Sebbah

Light scattering and localization in strongly scattering disordered systems is governed by the nature of the underlying eigenmodes, specially their spatial extension within the system. One of the main challenges in studying experimentally Anderson like localized states resides in the difficulty to excite these states independently and observe them individually anywhere in the sample. The modes mutual interaction and their coupling to the sample boundaries makes it extremely challenging to isolate them spectrally and image them alone. In the presence of gain, random lasing occurs above threshold and lasing modes are excited. It was shown recently that shaping the intensity profile of the optical pump is a very effective way to control and force random lasing in singlemode regime at any desired emission wavelength. Active random media therefore offer a unique platform to select modes individually. By using pump shaping technique in a strongly scattering random laser, we successfully select localized lasing modes individually. Direct imaging of the light distribution within the random laser confirms the confined nature of the modes and enables us to elucidate long standing questions on the role of non-Hermiticity in active scattering media and the influence of nonlinearities on Anderson wave localization.

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Oct 2020 • Nano letters

Cathodoluminescence Nanoscopy of 3D Plasmonic Networks

Racheli Ron, Marcin Stefan Zielinski, Adi Salomon

Nanoporous metallic networks are endowed with the distinctive optical properties of strong field enhancement and spatial localization, raising the necessity to map the optical eigenmodes with high spatial resolution. In this work, we used cathodoluminescence (CL) to map the local electric fields of a three-dimensional (3D) silver network made of nanosized ligaments and holes over a broad spectral range. A multitude of neighboring hotspots at different frequencies and intensities are observed at subwavelength distances over the network. In contrast to well-defined plasmonic structures, the hotspots do not necessarily correlate with the network morphology, emphasizing the complexity and energy dissipation through the network. In addition, we show that the inherent connectivity of the networked structure plays a key optical role because a ligament with a single connected linker shows localized modes whereas an …

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Oct 2020 • Physical Review B

Twinned nanostructure of thin films grown on r-cut sapphire

Anatoly G Shabalin, Elihu Anouchi, Nelson Hua, Yimin A Wu, Martin V Holt, Amos Sharoni, Oleg G Shpyrko

Due to strong electron-phonon interactions, strain engineering is a powerful tool to control quantum critical phenomena in strongly correlated oxides. Exploring this possibility requires understanding the nanoscale structure of quantum materials and the role it plays in forming the strain landscape. Here, we used a combination of x-ray nanoimaging and reciprocal space mapping to study the nanostructure of the archetypal Mott insulator VO 2, featuring an insulator-to-metal and structural phase transitions. We found that VO 2 thin films grown on r-cut sapphire consist of two intertwined crystal lattices, permanently inclined with respect to each other. This persistent pattern of twin domains stands out from the symmetry breaking induced by the structural phase transition and conceivably originates from the post-growth strain relaxation process. We propose a model explaining the formation of twin domains and the …

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Oct 2020 • Physical Review Research

Dark states of quantum search cause imperfect detection

Felix Thiel, Itay Mualem, Dror Meidan, Eli Barkai, David A Kessler

We consider a quantum walk where a detector repeatedly probes the system with fixed rate 1/τ until the walker is detected. This is a quantum version of the first-passage problem. We focus on the total probability P det that the particle is eventually detected in some target state, for example, on a node r d on a graph, after an arbitrary number of detection attempts. Analyzing the dark and bright states for finite graphs and more generally for systems with a discrete spectrum, we provide an explicit formula for P det in terms of the energy eigenstates which is generically τ independent. We find that disorder in the underlying Hamiltonian renders perfect detection, P det= 1, and then expose the role of symmetry with respect to suboptimal detection. Specifically, we give a simple upper bound for P det that is controlled by the number of equivalent (with respect to the detection) states in the system. We also extend our results to …

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Oct 2020 • Ternary and Multinary Compounds, 943-946, 2020

Sub-μm Semiconductor Device Structures in CuInSe2

S Richter, V Lyakhovitskaya, SR Cohen, Konstantin Gartsman, David Cahen, Y Manassen

We fabricate sub-micron sized diode and transistor structures (down to 100 nm in diameter) inside CuInSe2 crystals by inducing thermally assisted electromigration of mobile dopants. This is achieved by applying an electric field via a small area contact to the crystals, using a conducting Atomic Force Microscope tip. The structures are characterized by nm scale scanning spreading resistance - and scanning capacitance measurements to reveal the inhomogeneous doping profiles, that result from the electric field action. Calculations suggest that the smallest of the structures that we made are very close to the lower size limit of possible p/n/p devices.

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Oct 2020 • Desalination

Enhanced capacitive deionization of an integrated membrane electrode by thin layer spray-coating of ion exchange polymers on activated carbon electrode

Qinghao Wu, Dawei Liang, Eran Avraham, Izaak Cohen, Doron Aurbach, Shanfu Lu, Haining Wang, Yan Xiang

Capacitive deionization (CDI) has emerged as a novel desalination technology due to its cleanliness and low energy consumption. Despite being based on the principle of an electric double layer for ion adsorption on porous carbon materials, the inevitable faradaic reaction and the existence of co-ion repulsion reduce the charge efficiency (CE), leading to a low salt adsorption capacity (SAC). Herein, an integrated membrane electrode (IME), prepared by spray-coating a thin layer of an ion exchange polymer on the activated carbon (AC) electrode, effectively improves the selectivity of the electrode to the counter-ion, resulting in a high CE and high SAC with good stability. The results show that the CE of CDI performed using IMEs is between 70% and 98% during multiple adsorption-desorption cycles, and the SAC is up to 14–20 mg g−1, which is much higher than CE (35–65%) and SAC (7–13 mg g−1) of traditional …

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Oct 2020 • Physical Review Letters

Universal voltage fluctuations in disordered superconductors

Arnab Roy, Yuxiao Wu, Richard Berkovits, Aviad Frydman

The Aharonov-Casher effect is the analogue of the Aharonov-Bohm effect that applies to neutral particles carrying a magnetic moment. This effect can be manifested by vortices or fluxons flowing in trajectories that encompass an electric charge. These vortices have been predicted to result in a persistent voltage that fluctuates for different sample realizations. Here, we show that disordered superconductors exhibit reproducible voltage fluctuation, which is antisymmetrical with respect to the magnetic field, as a function of various parameters such as the magnetic field amplitude, field orientations, and gate voltage. These results are interpreted as the vortex equivalent of the universal conductance fluctuations typical of mesoscopic disordered metallic systems. We analyze the data in the framework of random matrix theory and show that the fluctuation correlation functions and curvature distributions exhibit behavior that …

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Oct 2020 • Biomedical optics express

Single wavelength measurements of absorption coefficients based on iso-pathlength point

I Feder, H Duadi, D Fixler

In optical sensing, to reveal the chemical composition of tissues, the main challenge is isolating absorption from scattering. Most techniques use multiple wavelengths, which adds an error due to the optical pathlength differences. We suggest using a unique measurement angle for cylindrical tissues, the iso-pathlength (IPL) point, which depends on tissue geometry only (specifically the effective radius). We present a method for absorption assessment from a single wavelength at multiple measurement angles. The IPL point presented similar optical pathlengths for different tissues, both in simulation and experiments, hence it is optimal. Finally, in vivo measurements validated our proposed method.

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Oct 2020 • Ternary and Multinary Compounds, 727-732, 2020

Dopant electromigration and device stability in ternary and multinary semiconductors

David Cahen

A doped semiconductor can be viewed as a mixed electronic-ionic conductor, with the dopants as mobile ions. Normally the temperature range where this becomes true is not even close to that where the (opto)electronic properties of the material are of interest. However notable exceptions exist and some examples of these are reviewed here. We limit ourselves to those cases where semiconductivity is preserved when the (mobile) dopant concentration changes and ambipolar behaviour can be obtained by dopant mobility. Dopant diffusion and drift are of interest not only in materials such as Si:Li, known from its use in radiation detectors, but also in ternary semiconductors, such as (Hg,Cd)Te and CuInSe2. Understanding the phenomena is important not only for low-temperature doping, but also because of the implications that it has for device miniaturization, as dopant diffusion and drift impose chemical limits on …

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Oct 2020 • Cell death & disease

miR-504 modulates the stemness and mesenchymal transition of glioma stem cells and their interaction with microglia via delivery by extracellular vesicles

Ariel Bier, Xin Hong, Simona Cazacu, Hodaya Goldstein, Daniel Rand, Cunli Xiang, Wei Jiang, Hiba Waldman Ben-Asher, Moshe Attia, Aharon Brodie, Ruicong She, Laila M Poisson, Chaya Brodie

Glioblastoma (GBM) is a highly aggressive tumor with poor prognosis. A small subpopulation of glioma stem cells (GSCs) has been implicated in radiation resistance and tumor recurrence. In this study we analyzed the expression of miRNAs associated with the functions of GSCs using miRNA microarray analysis of these cells compared with human neural stem cells. These analyses identified gene clusters associated with glioma cell invasiveness, axonal guidance, and TGF-β signaling. miR-504 was significantly downregulated in GSCs compared with NSCs, its expression was lower in GBM compared with normal brain specimens and further decreased in the mesenchymal glioma subtype. Overexpression of miR-504 in GSCs inhibited their self-renewal, migration and the expression of mesenchymal markers. The inhibitory effect of miR-504 was mediated by targeting Grb10 expression which acts as an oncogene …

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Oct 2020 • Ternary and Multinary Compounds, 103-106, 2020

Growth and characterization of twin-free CuInSe2 crystals by the traveling heater method

Vera Lyahovitskaya, Shachar Richter, Yishay Manassen, David Cahen

By growing CuInSe2 with the traveling heater method, from an In melt (at a temperature below that of the sphalerite-chalcopyrite transition), twinning in the resulting single crystals was suppressed. The resulting crystals were n-type and could be converted to p-type by Se anneal. Both types were characterized structurally by X-ray diffraction, for composition by microprobe analyses, morphologically by AFM and SEM, and electrically. They were found to be mostly homogeneous, with mirror-like cleavage and without twins.

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Oct 2020 • Ternary and Multinary Compounds, 67-70, 2020

Single crystal synchrotron X-ray diffraction of CuInSe2

Felix Frolow, Leonid Chernyak, David Cahen, Hanna Hallak, Jamal Gabboun, Åke Kvick, Heinz Graafsma

The structure of CuInSe2 was redetermined, using synchrotron X-radiation with 0.15Å wavelength, thus eliminating problems of uncertainties introduced by absorption corrections. This allowed us to look at the effect of subjecting crystals to strong electric fields, a process known to be able to type convert the material under relatively mild conditions. Proper refinement became possible after correcting for twinning. The main results are relatively high Cu temperature factors and significant electron density in octahedral interstitial sites. The main results of electric field application are a decrease in structure quality (increased R factor) and a slight increase in electron density on Cu sites. These preliminary results point to the need for further work with twin-free crystals.

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