Publications

A high-performance parallel computational platform for ion optics and ion motion dynamics simulations using graphics processing units of desktop computers

No abstract is provided for this article.

Strong exciton-photon coupling in monolayer heterostructures in tunable microcavities

Strong light-matter interaction in two-dimensional molybdenum diselenide (MoSe2) is observed using a tunable optical microcavity. Polariton states with a Rabi splitting of 20 and 29 meV are observed for a monolayer MoSe2 and a 'double-well' MoSe2/hBN/MoSe2, respectively.

Highly Conductive, Scalable, and Machine Washable Graphene‐Based E‐Textiles for Multifunctional Wearable Electronic Applications

Graphene‐based textiles show promise for next‐generation wearable electronic applications due to their advantages over metal‐based technologies. However, current reduced graphene oxide (rGO)‐based electronic textiles (e‐textiles) suffer from poor electrical conductivity and higher power consumption. Here, highly conductive, ultraflexible, and machine washable graphene‐based wearable e‐textiles are reported. A simple and scalable pad−dry−cure method with subsequent roller compression and a fine encapsulation of graphene flakes is used. The graphene‐based wearable e‐textiles thus produced provide lowest sheet resistance (≈11.9 Ω sq −1 ) ever reported on graphene e‐textiles, and highly conductive even after 10 home laundry washing cycles. Moreover, it exhibits extremely high flexibility, bendability, and compressibility as it shows repeatable response in both forward and backward directions before and after home laundry washing cycles. The scalability and multifunctional applications of such highly conductive graphene‐based wearable e‐textiles are demonstrated as ultraflexible supercapacitor and skin‐mounted strain sensors.

Condensed Matter Science / High Field Magnet Laboratory (HFML)

Chiral photonic super-crystals based on helical van der Waals homostructures

Chirality is probably the most mysterious among all symmetry transformations. Very readily broken in biological systems, it is practically absent in naturally occurring inorganic materials and is very challenging to create artificially. Chiral optical wavefronts are often used for the identification, control and discrimination of left- and right-handed biological and other molecules. Thus, it is crucially important to create materials capable of chiral interaction with light, which would allow one to assign arbitrary chiral properties to a light field. In this paper, we utilized van der Waals technology to assemble helical homostructures with chiral properties (e. g. circular dichroism). Because of the large range of van der Waals materials available such helical homostructures can be assigned with very flexible optical properties. We demonstrate our approach by creating helical homostructures based on multilayer As$_2$S$_3$, which offers the most pronounced chiral properties even in thin structures due to its strong biaxial optically anisotropy. Our work showcases that the chirality of an electromagnetic system may emerge at an intermediate level between the molecular and the mesoscopic one due to the tailored arrangement of non-chiral layers of van der Waals crystals and without additional patterning.

TRANSVERSE SPIN TRANSPORT IN GRAPHENE

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.

Cross sectional STEM imaging and analysis of multilayered two dimensional crystal heterostructure devices

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

Native bismuth, tsumoite, and Pb-bearing tsumoite from the Tarn’er copper-zinc massive sulfide deposit, northern Urals

No abstract is provided for this article.

Strong Suppression of Weak Localization in Graphene

Low-field magnetoresistance is ubiquitous in low-dimensional metallic systems with high resistivity and well understood as arising due to quantum interference on self-intersecting diffusive trajectories. We have found that in graphene this weak-localization magnetoresistance is strongly suppressed and, in some cases, completely absent. The unexpected observation is attributed to mesoscopic corrugations of graphene sheets which can cause a dephasing effect similar to that of a random magnetic field.

Making graphene visible

Microfabrication of graphene devices used in many experimental studies currently relies on the fact that graphene crystallites can be visualized using optical microscopy if prepared on top of Si wafers with a certain thickness of SiO2. The authors study graphene’s visibility and show that it depends strongly on both thickness of SiO2 and light wavelength. They have found that by using monochromatic illumination, graphene can be isolated for any SiO2 thickness, albeit 300nm (the current standard) and, especially, ≈100nm are most suitable for its visual detection. By using a Fresnel-law-based model, they quantitatively describe the experimental data.

van der Waals Materials for Overcoming Fundamental Limitations in Photonic Integrated Circuitry

With the advance of on-chip nanophotonics, there is a high demand for high-refractive-index and low-loss materials. Currently, this technology is dominated by silicon, but van der Waals (vdW) materials with a high refractive index can offer a very advanced alternative. Still, up to now, it was not clear if the optical anisotropy perpendicular to the layers might be a hindering factor for the development of vdW nanophotonics. Here, we studied WS2-based waveguides in terms of their optical properties and, particularly, in terms of possible crosstalk distance. Surprisingly, we discovered that the low refractive index in the direction perpendicular to the atomic layers improves the characteristics of such devices, mainly due to expanding the range of parameters at which single-mode propagation can be achieved. Thus, using anisotropic materials offers new opportunities and novel control knobs when designing nanophotonic devices.

Nobel Lecture: Graphene: Materials in the Flatland

Much like the world described in Abbott's Flatland, graphene is a two-dimensional object. And, as ``Flatland'' is ``a romance of many dimensions,'' graphene is much more than just a flat crystal. It possesses a number of unusual properties which are often unique or superior to those in other materials. In this brief lecture I would like to explain the reason for my (and many other people's) fascination with this material, and invite the reader to share some of the excitement I've experienced while researching it.

High-pressure Raman spectroscopy of graphene

In situ high-pressure Raman spectroscopy is used to study monolayer, bilayer, and few-layer graphene samples supported on silicon in a diamond anvil cell to 3.5 GPa. The results show that monolayer graphene adheres to the silicon substrate under compressive stress. A clear trend in this behavior as a function of graphene sample thickness is observed. We also study unsupported graphene samples in a diamond anvil cell to 8 GPa and show that the properties of graphene under compression are intrinsically similar to graphite. Our results demonstrate the differing effects of uniaxial and biaxial strain on the electronic band structure.

Suppressed weak (anti)localization in graphene

No abstract is provided for this article.

Graphene‐Based Oscillators for Biomimetic Neuro‐Interfaces

Abstract Chemical oscillators—such as the Belousov‐Zhabotinsky reaction—have long served as model systems for studying non‐equilibrium chemical dynamics and as analogues of biological oscillations. However, many biological processes rely on out‐of‐equilibrium, often oscillatory, ionic fluxes that do not involve chemical reactions. Examples include action potentials in neurons, muscle contraction, cardiac rhythmicity, intracellular calcium signaling, and calcium wave oscillations. Despite these parallels, the development of biomimetic systems compatible with neuromorphic interfaces remains a significant challenge. Here, a strategy is demonstrated to organize oscillating ionic currents by developing ionic transistors composed of graphene oxide and polyelectrolyte, and assembling them into all‐ionic integrated circuits. By driving these systems out of equilibrium using external voltages, periodic motion of various ions across defined interfaces is achieved. This behavior, governed by local electric fields arising from unbalanced ionic concentrations, closely mimics biological excitability, such as that observed in neuronal and cardiac systems. These ionic transistors serve as a foundational building block for neuromorphic interfaces, offering a universal platform to emulate complex biological ionic processes with high fidelity.

Quantum tunnelling with tunable spin geometric phases in van der Waals antiferromagnets

No abstract is provided for this article.

Mineral forms of tungsten at the Porokhovskoe and Yugo-Konevskoe deposits (South Urals)

The ore hand specimens and technological ore samples from the Porokhovskoe and Yugo-Konevskoe W greisen deposits in the South Urals are studied. The major W minerals of primary ores at both deposits include hubnerite and scheelite. The secondary and accessory minerals are pyrite, chalcopyrite and molybdenite, rare minerals include sphalerite, galena, bismuthinite, aikinite, unidentifed chalcogenides and sulfosalts, magnetite, rutile, ilmenite, titanite and columbite. The veins are mainly composed of quartz and muscovite with subordinate calcite, dolomite and fuorite, rare chlorite and amphibole and accessory zircon, apatite and uraninite. No zonation in the distribution of wolframite with various Fe content is identifed relative to the Yugo-Konevsky granite pluton, however, wolframite of the Northern area of the Porokhovskoe deposit is enriched in Fe compared to that of the Central area and Yugo-Konevskoe deposit. In addition to veined wolframite and scheelite, the oxidized ores also contain Fe and Mn oxyhydroxides, malachite, pyromorphite and bromargyrite. Tungsten is part of Mn and Fe oxyhydroxides, which replace wolframite and less often sulfdes. The WO3 content of pseudomorphic Mn and Fe oxyhydroxides after hubnerite reaches 18 wt. %. Single grains of stolzite and russellite are found. According to the results of phase chemical analysis of technological samples, the amount of tungstite in oxidized ores is minor, therefore all ores of both deposits were ascribed to primary type. Keywords: South Urals, Porokhovskoe deposit, Yugo-Konevskoe deposit, tungsten, hubnerite, scheelite, stolzite, trace elements.

Graphene-hexagonal boron nitride resonant tunneling diodes as high-frequency oscillators

We assess the potential of two-terminal graphene-hBN-graphene resonant tunneling diodes as high-frequency oscillators, using self-consistent quantum transport and electrostatic simulations to determine the time-dependent response of the diodes in a resonant circuit. We quantify how the frequency and power of the current oscillations depend on the diode and circuit parameters including the doping of the graphene electrodes, device geometry, alignment of the graphene lattices, and the circuit impedances. Our results indicate that current oscillations with frequencies of up to several hundred GHz should be achievable.