BINA

Topological insulators (TIs) are a class of materials characterized by an insulting bulk and high mobility topologically protected surface states, making them promising candidates for future optoelectronic and quantum devices. Although their electronic and transport properties have been extensively studied, their optical properties and prospective photonic capabilities have not been fully uncovered. Here, we use a combination of far-field and near-field nanoscale imaging and spectroscopy, to study CVD grown Bi2Se3 nanobeams (NBs). We first extract the mid-infrared (MIR) optical constants of Bi2Se3, revealing refractive index values as high as n ~6.4, and demonstrate that the NBs support Mie-resonances across the MIR. Local near-field reflection phase mapping reveals domains of various phase shifts, providing information on the local optical properties of the NBs. We experimentally measure up to 2{\pi} phase-shift across the resonance, in excellent agreement with FDTD simulations. This work highlights the potential of TI Bi2Se3 for quantum circuitry, non-linear generation, high-Q metaphotonics, and IR photodetection.

Chemical pollutants in drinking water can have many sources, such as pharmaceutical waste, agricultural runoff, and industrial discharges1, 2, 3. The development of a reliable, sensitive, and handheld sensor for the detection of a mixture of contaminants is important, both for human health and the environment. Herein, we show the development of a plasmonic sensor for Surface-enhanced Raman spectroscopy (SERS) and colorimetry measurements. Two types of plasmonic surfaces which enhance the electromagnetic field are presented here;(i) Well-defined cavities milled in silver substrates which are covered with 5 nm of SiO2 for stability.(ii) A scalable metallic-like aerogel network with large surface area, for increasing the sensitivity of our measurements. Three different families of analytes were studied, which can be found in drinking water: Piperidine and its derivatives (Pharmaceutical waste), Dioxins & Polychlorinated biphenyls, Per-and polyfluoroalkyl substances, each of which is toxic, both to the environment and humans health, even at a low concentration of 30 mg/Kg (3* 10-4M). Those

A major challenge in the development of quantum technologies is to induce additional types of ferroic orders into materials that exhibit other useful quantum properties. Various techniques have been applied to this end, such as elastically straining, doping, or interfacing a compound with other materials. Plastic deformation introduces permanent topological defects and large local strains into a material, which can give rise to qualitatively new functionality. Here we show via local magnetic imaging that plastic deformation induces robust magnetism in the quantum paraelectric SrTiO3, in both conducting and insulating samples. Our analysis indicates that the magnetic order is localized along dislocation walls and coexists with polar order along the walls. The magnetic signals can be switched on and off in a controllable manner with external stress, which demonstrates that plastically deformed SrTiO3 is a quantum multiferroic. These results establish plastic deformation as a versatile platform for quantum materials engineering.

The short time (large energy) behavior of the Sachdev-Ye-Kitaev model (SYK) is one of the main motivation to the growing interest garnered by this model. True chaotic behaviour sets in at the Thouless time, which can be extracted from the energy spectrum. In order to do so, it is necessary to unfold the spectrum, i.e., to filter out global tendencies. Using a simple ensemble average for unfolding results in a parametically low estimation of the Thouless energy. By examining the behavior of the spectrum as the distribution of the matrix elements is changed into a log-normal distribution it is shown that the sample to sample level spacing variance determines this estimation of the Thouless energy. Using the singular value decomposition method, SVD, which filters out these sample to sample fluctuations, the Thouless energy becomes parametrically much larger, essentially of order of the band width. It is shown that the SYK model in non-self-averaging even in the thermodynamic limit which must be taken into account in considering its short time properties.

Composite solid electrolytes with ceramic particles dispersed in a polymer matrix are considered a correct choice for all-solid-state batteries. These electrolytes balance the high ionic conductivity of superionic-ceramic conductors and the elasticity of polymers. Here, Li||LiFePO4 batteries with 30 wt% of Li1.3Al0.3Ti1.7(PO4)3 (LATP) embedded in PEO20:LiTFSI show superior performance at elevated temperature. After ~150 cycles, cells retained 84% of their original capacity compared to only 51% for batteries with no additive. At 5C cells demonstrate 43% higher capacity. In symmetric cells with blocking and non-blocking electrodes and all-solid-state batteries LATP lowers the impedance of the electrode-electrolyte interface ensuring cycling stability. LATP improves performance by stabilization of the cathode-electrolyte interface, apparently the major contributor to the cell impedance.

Broad area laser diodes are attractive for the high optical power they can produce. Unfortunately, this high power normally comes at the cost of severely reduced spatial coherence since the wide area of the semiconductor wave-guide is inherently spatially multi-mode (in the slow axis). We demonstrate a method to majorly improve the spatial coherence of a high-power broad-area diode laser by placing it in an external cavity that is mode selective. We design the cavity, such that the diode aperture acts as its own spatial filter, obviating the need for an intra-cavity slit-filter, and optimally utilizing the entire gain medium. We demonstrate this soft filtering method using wide diodes of and widths and compare its power-efficiency to the standard approach of hard-filtering with a slit. We obtain high-gain operation in a pure single-mode, demonstrating up to CW power at with high beam quality.

Recent research on two-dimensional (2D) transition metal dichalcogenides (TMDCs) has led to remarkable discoveries of fundamental phenomena and to device applications with technological potential. Large-scale TMDCs grown by chemical vapor deposition (CVD) are now available at continuously improving quality, but native defects and natural degradation in these materials still present significant challenges. Spectral hysteresis in gate-biased photoluminescence (PL) measurements of WSe2 further revealed long-term trapping issues of charge carriers in intrinsic defect states. To address these issues, we apply here a two-step treatment with organic molecules, demonstrating the “healing” of native defects in CVD-grown WSe2 and WS2 by substituting atomic sulfur into chalcogen vacancies. We uncover that the adsorption of thiols provides only partial defect passivation, even for high adsorption quality, and …

We present recent measurements of nonlinear x-ray optical mixing in silicon. These measurements demonstrate how x-ray optical mixing can measure details of the atomic-scale nonlinear electron dynamics that are invisible to purely optical techniques.

The development of platinum group metal-free catalysts is considered the most prominent path for reducing the cost of low-temperature fuel cells (LTFC). Despite the great advancement in the field, its further progress is currently limited by the ability to understand and mitigate the catalysts’ degradation mechanisms, which up to recent years was limited by the lack of activity descriptors. Recent work showed that this could be solved using Fourier-transformed alternating current voltammetry that enables to deconvolute Faradaic currents arising from the redox reaction of the active sites from the capacitive currents, and by that accurately measure the electrochemically active site density of these catalysts in situ fuel cells. However, the analysis of the results can be complex, requiring simulation software for accurate parameter extraction. Herein, a simplified analysis of Fourier-transformed alternating current voltammetry is …

In this paper a novel method for microwave based remote sensing of vital signs behind walls is presented. The method is based on temporal spatial analysis of back scattered microwave signals. The use of non-optical electromagnetic radiation enables monitoring from larger distances and behind objects in contrast to similar concepts in optics. Further, such use of non-optical radiation omits the need for direct line of sight between the monitoring system and the target and enables monitoring through walls or other barriers. Micro-vibrations due to breathing and heart pulsation affect the reflection of microwaves and cause the self-interference random patterns (i.e. speckle patterns) to vary in time and space. By using this approach, the temporal change of the speckle patterns due to changes in vital signs can be tracked behind walls. In this paper we present a system in WiFi frequencies band consisting of two radio …

We propose and demonstrate a holographic imaging scheme exploiting random illuminations for recording hologram and then applying numerical reconstruction and twin image removal. We use an in-line holographic geometry to record the hologram in terms of the second-order correlation and apply the numerical approach to reconstruct the recorded hologram. This strategy helps to reconstruct high-quality quantitative images in comparison to the conventional holography where the hologram is recorded in the intensity rather than the second-order intensity correlation. The twin image issue of the in-line holographic scheme is resolved by an unsupervised deep learning based method using an auto-encoder scheme. Proposed learning technique leverages the main characteristic of autoencoders to perform blind single-shot hologram reconstruction, and this does not require a dataset of samples with available …

Localized surface plasmon resonance (LSPR) holds great promise for the next generation of fast nanoscale optoelectronic devices, as silicon-based electronic devices approach fundamental speed and scaling limitations. However, in order to fully exploit the potential of plasmonics, devices and material systems capable of actively controlling and manipulating plasmonic response are essential. Here, we demonstrate active control of the electric field distribution of a microantenna by coupling LSPRs to a photosynthetic protein with outstanding optoelectronic properties and a long-range and efficient exciton transfer ability. The hybrid biosolid state active platform is able to tune and modulate the optical activity of a microplasmonic antenna via the interaction of the bioactive material with plasmon oscillations occurring in the antennae. In addition, we demonstrate that the effect of the coupling can be further enhanced …

Courtship behaviors in Drosophila melanogaster are innate and contain highly stereotyped but also experience-and state-dependent elements. They have been the subject of intense study for more than 100 years. The power of Drosophila as a genetic experimental system has allowed the dissection of reproductive behaviors at a molecular, cellular, and physiological level. As a result, we know a great deal about how flies perceive sensory cues from potential mates, how this information is integrated in higher brain centers to execute reproductive decisions, and how state and social contexts modulate these responses. The simplicity of the assay has allowed for its broad application. Here, we introduce methods for studying male and female innate reproductive behaviors as well as their plastic responses.

Localized surface plasmon resonance (LSPR) holds great promise for the next generation of fast nanoscale optoelectronic devices, as silicon-based electronic devices approach fundamental speed and scaling limitations. However, in order to fully exploit the potential of plasmonics, devices and material systems capable of actively controlling and manipulating plasmonic response are essential. Here, we demonstrate active control of the electric field distribution of a microantenna by coupling LSPRs to a photosynthetic protein with outstanding optoelectronic properties and a long-range and efficient exciton transfer ability. The hybrid biosolid state active platform is able to tune and modulate the optical activity of a microplasmonic antenna via the interaction of the bioactive material with plasmon oscillations occurring in the antennae. In addition, we demonstrate that the effect of the coupling can be further enhanced …

We present an experimental study of bilayers of a disordered Ag metal layer close to the metal-insulator transition and an indium-oxide film which is on the insulating side of the superconductor insulator transition. Our results show that superconducting fluctuations within the indium-oxide film, that proximitize the underlying metal layer, induce insulating rather than superconducting behavior. This is ascribed to suppression of density of states (due to the superconducting energy gap) for quasiparticles in the proximitized regions. Our results present a manifestation of the proximity effect phenomenon and provide important insight into the nature of the insulating phase of the disorder driven superconductor insulator transition.

This special issue is dedicated to the memory of Shimon Vega (1943–2021) with contributions from former students, postdocs, and other close colleagues. Shimon had seminal contributions in magnetic resonance, including in the areas of nuclear quadrupole resonance (NQR), solid-state NMR, and dynamic nuclear polarization (DNP). While dedicating a major effort to the development of NMR theory, he always made direct connections to experiments and relevant applications and was a gifted educator and teacher. The content of this special issue is a manifestation of these various facets in his personality.Matysik highlights, in his paper, the educational spirit of Shimon by describing the “Vega diagrams”; block representations of Hamiltonians and density matrices with pathways directing the reader to the relevant physics. On the theoretical side, the work of Sajith et al. extracts effective Hamiltonians and key …

We propose a cheating strategy to a relativistic quantum commitment scheme (Nadeem, 2014) which was claimed to be unconditionally secure. It is shown that the sender Alice can cheat successfully with probability 100%, thus disproving the security claim.

The temperature-dependence of the chirality-induced spin selectivity (CISS) effect can be used to discriminate between different theoretical proposals for the mechanism of the CISS effect. Here, we briefly review key experimental results and discuss the effect of temperature in different models for the CISS effect. We then focus on the recently suggested spinterface mechanism and describe the different possible effects temperature can have within this model. Finally, we analyze in detail recent experimental results presented in the work of Qian et al.[Nature 606, 902–908 (2022)] and demonstrate that, contrary to the original interpretation by the authors, these data actually indicate that the CISS effect increases with decreasing temperature. Finally, we show how the spinterface model can accurately reproduce these experimental results.

Scattering-type scanning near-field optical microscopy is a powerful imaging technique for studying materials beyond the diffraction limit. However, interpreting near-field measurements poses challenges in mapping the response of polaritonic structures to meaningful physical properties. To address this, we propose a theory based on the transfer matrix method to simulate the near-field response of 1D polaritonic structures. Our approach provides a computationally efficient and accurate analytical theory, relating the near-field response to well-defined physical properties. This work enhances the understanding of near-field images and complex polaritonic phenomena. Finally, this scattering theory can extend to other systems like atoms or nanoparticles near a waveguide.

Since 2011, 2D transition metal carbides, carbonitrides and nitrides known as MXenes have gained huge attention due to their attractive chemical and electronic properties. The diverse functionalities of MXenes make them a promising candidate for multitude of applications. Recently, doping MXene with metallic and non-metallic elements has emerged as an exciting new approach to endow new properties to this 2D systems, opening a new paradigm of theoretical and experimental studies. In this review, we present a comprehensive overview on the recent progress in this emerging field of doped MXenes. We compare the different doping strategies; techniques used for their characterization and discuss the enhanced properties. The distinct advantages of doping in applications such as electrocatalysis, energy storage, photovoltaics, electronics, photonics, environmental remediation, sensors, and biomedical …