Publications

The paper examines mineralogy of noble metals and ore formation conditions at the Naily gold deposit (South Urals), which is hosted in pyrite-bearing talc-carbonate, chlorite-quartz-carbonate and quartz-carbonate metasomatites after serpentinites and rocks of a gabbrodiorite-plagiogranite complex. Based on microscopic and electron microscopic studies of polished sections and heavy concentrates, it is established that native gold and Au tellurides are the major Au minerals of veins, metasomatites after intermediate and felsic intrusive rocks and foliated serpentinites. Native gold occurs as: 1) inclusions in pyrite and rarely in chalcopyrite, 2) free particles associated with non-metallic minerals, which probably fll interstitions, 3) interstitial forms in pyrite aggregates often together with chalcopyrite, galena and sphalerite, and veinlets in hessite, 4) fne inclusions in tetradymite and 5) inclusions in limonite. Tellurides of noble metals include calaverite, petzite, hessite and an unidentifed Ag and Pb sulfotelluride. Silver is also incorporated in acanthite and Hg-Ag-Sb-As, Pb-Bi-Ag and Cu-Ag-Pb-Bi sulfosalts. The Ag content of free native gold is 10–16 wt. % increasing to 20–24 wt. % in native gold in pyrite and in assemblage with hessite. Altaite, coloradoite and Ni and Pd tellurides are found in assemblages similar to noble metal mineralization. The formation temperature of chlorite from ore-bearing metasomatites is 339–392 °C. Fluid inclusions in quartz, calcite and albite are homogenized at a temperature range of 162–377 °C. The eutectic temperature (–23.5 °C) is typical of NaCl-KCl-H2O system. The ice melting temperature varies from –0.5 to –3.7 °C corresponding to salinity of 0.9– 6.0 wt. % NaCl-equiv.

The topological structure associated with the branchpoint singularity around an exceptional point (EP) provides new tools for controlling the propagation of electromagnetic waves and their interaction with matter. To date, observation of EPs in light-matter interactions has remained elusive and has hampered further progress in applications of EP physics. Here, we demonstrate the emergence of EPs in the electrically controlled interaction of light with a collection of organic molecules in the terahertz regime at room temperature. We show, using time-domain terahertz spectroscopy, that the intensity and phase of terahertz pulses can be controlled by a gate voltage which drives the device across the EP. This fully electrically-tuneable system allows reconstructing the Riemann surface associated with the complex energy landscape and provides a topological control of light by tuning the loss-imbalance and frequency detuning of interacting modes. We anticipate that our work could pave the way for new means of dynamic control on the intensity and phase of terahertz field, developing topological optoelectronics, and studying the manifestations of EP physics in the quantum correlations of the light emitted by a collection of emitters coupled to resonators.

ABSTRACT Wearable electronic textiles (e‐textiles) present a transformative platform for integrating real‐time health monitoring devices into everyday garments. Despite their promise, the development of flexible, efficient, and reliable on‐body energy storage remains a major bottleneck. Inkjet printing, known for its precision and compatibility with various substrates, emerges as a viable method for fabricating energy devices on textiles. Metal–organic frameworks (MOFs) have shown great promise in prior studies for enabling flexible and high‐performance energy storage in wearable electronics. Here, we present a novel strategy for engineering metal–organic framework (MOF)‐based e‐textiles as electrodes for a solid‐state textile supercapacitor, utilizing inkjet printing technology. For the first time, standalone MOF inks were successfully deposited on textile substrates, producing highly flexible and washable conductive fabrics. These MOF‐integrated textiles functioned as supercapacitor electrodes, achieving outstanding electrochemical performance with areal and gravimetric capacitances reaching ~354 mF cm −2 and ~87 F g −1 , at a 1 mV s −1 scan rate respectively. The devices also demonstrated a high energy density of approximately 196 μW h cm −2 with a remarkable power density of ~54 385 μW cm −2 , with nearly 99% retention after 1000 charge–discharge cycles. These results establish MOF‐based e‐textiles as a promising avenue for the next‐generation of wearable energy storage systems. image

Tunneling conductance between two bilayer graphene (BLG) sheets separated by 2 nm-thick insulating barrier was measured in two devices with the twist angles between BLGs less than 1°. At small bias voltages, the tunneling occurs with conservation of energy and momentum at the points of intersection between two relatively shifted Fermi circles. Here, we experimentally found and theoretically described signatures of electron-hole asymmetric band structure of BLG: since holes are heavier, the tunneling conductance is enhanced at the hole doping due to the higher density of states. Another key feature of BLG that we explore is gap opening in a vertical electric field with a strong polarization of electron wave function at van Hove singularities near the gap edges. This polarization, by shifting electron wave function in one BLG closer to or father from the other BLG, gives rise to asymmetric tunneling resonances in the conductance around charge neutrality points, which result in strong sensitivity of the tunneling current to minor changes of the gate voltages. The observed phenomena are reproduced by our theoretical model taking into account electrostatics of the dual-gated structure, quantum capacitance effects, and self-consistent gap openings in both BLGs.

No abstract is provided for this article.

We present a joint theoretical and experimental investigation of charge doping and electronic potential landscapes in hybrid structures composed of graphene and semiconducting single layer molybdenum disulfide (MoS2). From first-principles simulations, we find electron doping of graphene due to the presence of rhenium impurities in MoS2. Furthermore, we show that MoS2 edges give rise to charge reordering and a potential shift in graphene, which can be controlled through external gate voltages. The interplay of edge and impurity effects allows the use of the graphene-MoS2 hybrid as a photodetector. Spatially resolved photocurrent signals can be used to resolve potential gradients and local doping levels in the sample.

No abstract is provided for this article.

Recent dramatic progress in studying various two-dimensional (2D) atomic crystals and their heterostructures calls for better and more detailed understanding of their crystallography, reconstruction, stacking order, etc. For this, direct imaging and identification of each and every atom is essential. Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) are ideal and perhaps the only tools for such studies. However, the electron beam can in some cases induce dramatic structure changes, and radiation damage becomes an obstacle in obtaining the desired information in imaging and chemical analysis in the (S)TEM. This is the case of 2D materials such as molybdenum disulfide MoS2, but also of many biological specimens, molecules, and proteins. Thus, minimizing damage to the specimen is essential for optimum microscopic analysis. In this article we demonstrate, on the example of MoS2, that encapsulation of such crystals between two layers of graphene allows for a dramatic improvement in stability of the studied 2D crystal and permits careful control over the defect nature and formation in it. We present STEM data collected from single-layer MoS2 samples prepared for observation in the microscope through three distinct procedures. The fabricated single-layer MoS2 samples were either left bare (pristine), placed atop a single-layer of graphene, or finally encapsulated between single graphene layers. Their behavior under the electron beam is carefully compared, and we show that the MoS2 sample "sandwiched" between the graphene layers has the highest durability and lowest defect formation rate compared to the other two samples, for very similar experimental conditions.

Metal impurities, gold and nickel, have been deliberately introduced into boron-nitride (BN) sheets. The structural and topographic properties of doped BN have been studied by aberration corrected scanning transmission electron microscopy (STEM). Analysis revealed that metal atoms cluster preferentially in/on contaminated areas. The metal coverage on BN is almost the same for the same evaporated amount of 1 A.

No abstract is provided for this article.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

No abstract is provided for this article.

In this paper we report transverse spin transport properties of graphene in a device, where for the first time a mono-atomically thin atomic fabric was sandwiched between magnetic thin films. We found that a single layer graphene flake was sufficient to break the exchange coupling between magnetic films and also to enhance the magnetoresistance effect.

Journal Article Cross sectional STEM imaging and analysis of multilayered two dimensional crystal heterostructure devices Get access Sarah J Haigh, Sarah J Haigh School of Materials, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar Aidan P Rooney, Aidan P Rooney School of Materials, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar Eric Prestat, Eric Prestat School of Materials, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar Fred Withers, Fred Withers School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar O Del Pozo Zamudio, O Del Pozo Zamudio Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH, UK Search for other works by this author on: Oxford Academic Google Scholar Artem Mishchenko, Artem Mishchenko School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar Ali Gholinia, Ali Gholinia School of Materials, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar K Watanabe, K Watanabe National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan Search for other works by this author on: Oxford Academic Google Scholar T Taniguchi, T Taniguchi National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan Search for other works by this author on: Oxford Academic Google Scholar A I Tartakovskii, A I Tartakovskii Department of Physics and Astronomy, University of Sheffield, Sheffield, S3 7RH, UK Search for other works by this author on: Oxford Academic Google Scholar ... Show more Andre K Geim, Andre K Geim Manchester Centre for Mesoscience and Nanotechnology, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar Konstantin S Novoselov Konstantin S Novoselov School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 21, Issue S3, 1 August 2015, Pages 107–108, https://doi.org/10.1017/S1431927615001336 Published: 23 September 2015

No abstract is provided for this article.