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Golden nanoglue completes the wonder material

2018/10/092018/10/11

Modern microelectronics relies on semiconductors and their metal electrodes. High-performance device functionality demands high transistor density within a single chip, which soon will reach the physical limits of bulk materials. Alternatives have been found in atomically thin materials, e.g. graphene and its semiconductive inorganic relatives.

MoS₂ (molybdenum disulphide) is the representative inorganic layered crystal with properties similar to those of graphene. To be useful in applications, it must be joined to the metallic electrodes to enable charge flow between the metals and semiconductive (M/S) counterparts. In a recent study, scientists from University of Oulu, Finland have demonstrated the success of joining MoS₂to Ni (nickel) particles by using gold (Au) nanoglue as a buffer material. Through in-house observations and the first-principles calculations, the semiconductor and metal can be bridged either by the crystallized gold nanoparticles, or by the newly formed MoS₂-Au-Ni ternary alloy.
A metallic contact is formed, leading to enhanced electron mobility crossing the M/S interface.

Image: representation of gold nanoglue joining molybdenum disulphide and nickel.

Year of Engineering I23 Gripper Spotlight

2018/10/082018/10/11

Celebrating the Year of Engineering on Beamline I23

The Year of Engineering (UK) is all about celebrating the world and wonder of the industry, and exploring the wide range of ideas and innovations that Engineering involves. Today, we’re having a look at Diamond’s Beamline I23 – a specially designed instrument for protein crystallography that uses long wavelengths.
There are unique engineering scientific challenges involved in designing a system that will allow researchers to use long wavelengths of Synchrotron radiation effectively. The special cryogenically-cooled sample gripper on I23, is one of the solutions that makes this beamline successful. Learn more about this engineering innovation.

Molluscs use thermodynamics to create complex morphologies with exceptional properties

2018/10/082018/10/22

An international team has found how some molluscs create their complex structures.

Their work provides new tools for novel bioinspired and biomimetic bottom-up material design.
Nature serves as a source of inspiration for scientists and engineers thanks to the complex material architectures that make up some living organisms. These materials carry out essential functions, ranging from structural support and mechanical strength, to optical, magnetic or sensing capabilities. One example of this are molluscan shells, made of mineralized tissues organised in mineral-organic hierarchical functional architectures.

Molluscs appeared more than 500 million years ago, and they have developed hard and stiff mineralised outer shells for structural support and protection against predation. Their shells consist of mineral-organic composite structures made of calcium carbonates, mostly calcite and aragonite. The different shells exhibit a large variety of intricate three-dimensional assemblies with superior mechanical properties.

New clues to cut through the mystery of Titan’s atmospheric haze

2018/10/082018/10/12

A team including Berkeley Lab scientists homes in on a ‘missing link’ in Titan’s one-of-a-kind chemistry.

Saturn’s largest moon, Titan, is unique among all moons in our solar system for its dense and nitrogen-rich atmosphere that also contains hydrocarbons and other compounds, and the story behind the formation of this rich chemical mix has been the source of some scientific debate.
Now, a research collaboration involving scientists in the Chemical Sciences Division at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has zeroed in on a low-temperature chemical mechanism that may have driven the formation of multiple-ringed molecules – the precursors to more complex chemistry now found in the moon’s brown-orange haze layer.
The study, co-led by Ralf Kaiser at the University of Hawaii at Manoa and published in the Oct. 8 edition of the journal Nature Astronomy, runs counter to theories that high-temperature reaction mechanisms are required to produce the chemical makeup that satellite missions have observed in Titan’s atmosphere.

Image: The atmospheric haze of Titan, Saturn’s largest moon (pictured here along Saturn’s midsection), is captured in this natural-color image (box at left). A study that involved experiments at Berkeley Lab’s Advanced Light Source has provided new clues about the chemical steps that may have produced this haze.
Credits: NASA Jet Propulsion Laboratory, Space Science Institute, Caltech

Italy now European XFEL shareholder

2018/10/052018/10/08

On Friday 5 October, the Italian research organisations INFN and CNR officially became shareholders of European XFEL GmbH.

The National Institute for Nuclear Physics (INFN) and the National Research Council (CNR) together now own 2.9% of the company’s shares; one third going to INFN and two thirds to CNR. Italy has been a European XFEL partner country since the foundation of the company. With the acquisition of the shares, INFN and CNR – both designated by Italy as Italian shareholders – now also have full voting rights in the company’s supreme organ, the European XFEL Council. The Italian share of 2.9% in the company corresponds to the Italian contributions to the total European XFEL construction and operation budgets, making Italy the fourth largest funders following Germany, Russia, and France.

>Read more on the European XFEL website

Image: Representatives from DESY, European XFEL, INFN and CNR celebrate after the signing of the accession documents today. From left to right: Veronica Buccheri, INFN; Nicole Elleuche, European XFEL; Roberto Pellegrini, INFN; Rosario Spinella, CNR; Bruno Quarta, INFN; Reinhard Brinkmann, DESY; Robert Feidenhans’l, European XFEL; Christian Harringa, DESY.
Credit: European XFEL

New NSLS-II beamline illuminates electronic structures

2018/10/052018/10/30

MIT scientists conduct the first experiment at NSLS-II’s Soft Inelastic X-ray Scattering beamline.

On July 15, 2018, the Soft Inelastic X-ray Scattering (SIX) beamline at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at DOE’s Brookhaven National Laboratory—welcomed its first visiting researchers. SIX is an experimental station designed to measure the electronic properties of solid materials using ultrabright x-rays. The materials can be as small as a few microns—one millionth of a meter.
The first researchers to take advantage of the world-class capabilities at SIX were Jonathan Pelliciari and Zhihai Zhu, two scientists from the Massachusetts Institute of Technology (MIT). The pair used SIX to study a chromate sample, a fascinating material with novel applications in magnetism, batteries, and catalysis. Little was known about the electronic structure of the chromate sample the MIT team studied at SIX, and their research is aimed at unlocking the properties of this material. To do so, they needed the atomic sensitivity and energy resolution of the SIX beamline.

Picture: The sample chamber of the Soft Inelastic X-ray Scattering (SIX) beamline at NSLS-II allows scientists to mount their materials on a special holder that can be turned and moved into the beam of bright x-rays.

Impressions from the 30th MAX IV user meeting

2018/10/042018/10/11

At the 30^th MAX IV user meeting over 250 attendees met to discuss and learn for three days in Lund.

The impressions that we collected from the meeting are positive overall.
There was a very good atmosphere, good backup from the users, lively discussion, and full rooms for the parallel sessions. These are very important signs for for us going forward, says interim director Ian McNulty and science director Marjolein Thunnissen. We also talked to a few of the users who appreciated that the user meeting is a good place to meet with colleagues and collaborators to discuss and learn. The other comment that we got from several of them was that it was important that they now have a clear time plan and overview of the status so that they can plan for their experiments at MAX IV.

Nano-opto-electronics with Soapstone

2018/10/032018/10/23

Research shows potential of combining mineral with graphene for the design of new devices.

The development of electronic devices in the nanometric scale depends on the search for materials that have appropriate characteristics, and that are also efficient and inexpensive. This is the case of graphene, a material formed by a single layer of carbon atoms obtained from graphite. Graphene is a conductor with excellent optical and electrical properties that can be easily altered by the incidence of electric fields or light.

In addition, several other interesting structural, electronic and optical properties can be obtained by combining graphene with other materials. These new properties arise due to changes in the electronic structure in the interface of different materials when they are brought into contact. In this scenario, the search for new materials and ways of combining them becomes a natural trend.

Image: DOI: 10.1021/acsphotonics.7b01017

New approach to breast cancer detection

2018/10/032018/10/04

Phase contrast tomography shows great promise in early stages of study and is expected to be tested on first patients by 2020.

An expert group of imaging scientists in Sydney and Melbourne are using the Imaging and Medical Beamline (IMBL) at the Australian Synchrotron as part of ongoing research on an innovative 3D imaging technique to improve the detection and diagnosis of breast cancer.

The technique, known as in-line phase-contrast computed tomography (PCT), has shown advantages over 2D mammography with conventional X-rays by producing superior quality images of dense breast tissue with similar or below radiation dose.
Research led by Prof Patrick Brennan of the University of Sydney and Dr Tim Gureyev at the University of Melbourne with funding from the NHMRC and the support of clinicians in Melbourne including breast surgeon Dr Jane Fox, is now focused on demonstrating the clinical usefulness of the technique.
Together with Associate Professor Sarah Lewis and Dr SeyedamirTavakoli Taba from the University of Sydney heading clinical implementation, the technique is expected to be tested on the first patients at the Australian Synchrotron by 2020.

Image: CT reconstruction of 3D image of mastectomy sample revealing invasive carcinoma

Single atoms break carbon’s strongest bond

2018/10/022018/10/02

Scientists discovered that single atoms of platinum can break the bond between carbon and fluorine, one of the strongest known chemical bonds.

An international team of scientists including researchers at Yale University and the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new catalyst for breaking carbon-fluorine bonds, one of the strongest chemical bonds known. The discovery, published on Sept. 10 in ACS Catalysis, is a breakthrough for efforts in environmental remediation and chemical synthesis.

“We aimed to develop a technology that could degrade polyfluoroalkyl substances (PFAS), one of the most challenging pollutant remediation problems of the present day,” said Jaehong Kim, a professor in the department of chemical and environmental engineering at Yale University. “PFAS are widely detected all over the world, from Arctic biota to the human body, and concentrations in contaminated groundwater significantly exceed the regulatory limit in many areas. Currently, there are no energy-efficient methods to destroy these contaminants. Our collaboration with Brookhaven Lab aims to solve this problem by taking advantage of the unique properties of single atom catalysts.”

Image: Brookhaven scientist Eli Stavitski is shown at NSLS-II’s Inner Shell Spectroscopy beamline, where researchers imaged the physical and chemical complexity of a single-atom catalyst that breaks carbon-fluorine bonds.

First experiments reveal unknown structure of antibiotics killer

2018/10/022018/10/08

DESY-led international collaboration obtains first scientific results from European XFEL

An international collaboration led by DESY and consisting of over 120 researchers has announced the results of the first scientific experiments at Europe’s new X-ray laser European XFEL. The pioneering work not only demonstrates that the new research facility can speed up experiments by more than an order of magnitude, it also reveals a previously unknown structure of an enzyme responsible for antibiotics resistance. “The groundbreaking work of the first team to use the European XFEL has paved the way for all users of the facility who greatly benefit from these pioneering experiments,” emphasises European XFEL managing director Robert Feidenhans’l. “We are very pleased – these results show that the facility works even better than we had expected and is ready to deliver new scientific breakthroughs.” The scientists present their results, including the first new protein structure solved at the European XFEL, in the journal Nature Communications.

“Being at a totally new class of facility we had to master many challenges that nobody had tackled before,” says DESY scientist Anton Barty from the Center for Free-Electron Laser Science (CFEL), who led the team of about 125 researchers involved in the first experiments that were open to the whole scientific community. “I compare it to the maiden flight of a novel aircraft: All calculations and assembly completed, everything says it will work, but not until you try it do you know whether it actually flies.”

The 3.4 kilometres long European XFEL is designed to deliver X-ray flashes every 0.000 000 220 seconds (220 nanoseconds). To unravel the three-dimensional structure of a biomolecule, such as an enzyme, the pulses are used to obtain flash X-ray exposures of tiny crystals grown from that biomolecule. Each exposure gives rise to a characteristic diffraction pattern on the detector. If enough such patterns are recorded from all sides of a crystal, the spatial structure of the biomolecule can be calculated. The structure of a biomolecule can reveal much about how it works.

>Read more on the DESY website and on the European XFEL website

Image: Artist’s impression of the experiment: When the ultra-bright X-ray flashes (violet) hit the enzyme crystals in the water jet (blue), the recorded diffraction data allow to reconstruct the spatial structure of the enzyme (right).
Credit: DESY/Lucid Berlin

Diamond shines its light on moon rocks

2018/10/022018/10/03

Nearly 50 years after our first steps on the Moon, rock samples from the Apollo missions still have a lot to tell us about lunar formation, and Earth’s volcanoes.

An international collaboration involving scientists in Tenerife, the US and the UK, are using Diamond, the UK’s national synchrotron light source, to investigate Moon rocks recovered during the Apollo Missions in a brand new way.
Dr. Matt Pankhurst of Instituto Volcanológico de Canarias and NASA lunar principle investigator explains: “We have used a new imaging technique developed at Diamond to carry out 3D mapping of olivine – a common green mineral found in the Earth’s sub-surface and in these Moon rock samples. These maps will be used to improve understanding of the Moon’s ancient volcanic systems and help to understand active geological processes here on Earth.
With this new technique, our team may be able to recover from these Moon rock samples information such as what the patterns of magma flow within the volcanic system were, what the magma storage duration was like, and potentially even identify eruption triggers. The data will be analysed using state-of-the-art diffusion modelling which will establish the history of individual crystals.”

>Read more on the Diamond Light Source website

Image: Dr Matt Pankhurst studies one of the moon rock samples from the Apollo 12 & 15 missions at Diamond Light Source

Boosting the efficiency of silicon solar cells

2018/10/022018/10/08

The efficiency of a solar cell is one of its most important parameters.

It indicates what percentage of the solar energy radiated into the cell is converted into electrical energy. The theoretical limit for silicon solar cells is 29.3 percent due to physical material properties. In the journal Materials Horizons, researchers from Helmholtz-Zentrum Berlin (HZB) and international colleagues describe how this limit can be abolished. The trick: they incorporate layers of organic molecules into the solar cell. These layers utilise a quantum mechanical process known as singlet exciton fission to split certain energetic light (green and blue photons) in such a way that the electrical current of the solar cell can double in that energy range.

The principle of a solar cell is simple: per incident light particle (photon) a pair of charge carriers (exciton) consisting of a negative and a positive charge carrier (electron and hole) is generated. These two opposite charges can move freely in the semiconductor. When they reach the charge-selective electrical contacts, one only allows positive charges to pass through, the other only negative charges. A direct electrical current is therefore generated, which can be used by an external consumer.

Picture: Darstellung des Prinzips einer Silizium-Multiplikatorsolarzelle mit organischen Kristallen
Credit: M. Künsting/HZB

Towards oxide-integrated epitaxial graphene-based spin-orbitronics

2018/09/272018/09/28

An international team of researchers from IMDEA Nanociencia and Complutense and Autónoma universities in Madrid, the Institut Néel in Grenoble and the ALBA Synchrotron in Barcelona has elucidated a new property of Graphene/Ferromagnetic interfaces: the existence of a sizable magnetic unidirectional interaction, technically a Dzyaloshinskii–Moriya Interaction of Rashba origin, which is responsible for establishing a chiral character to magnetic domain wall structures.

A major challenge for future spintronics is to develop suitable spin transport channels with long spin lifetime and propagation length. Graphene can meet these requirements, even at room temperature. On the other side, taking advantage of the fast motion of chiral textures, that is, Néel-type domain walls and magnetic skyrmions, can satisfy the demands for high-density data storage, low power consumption, and high processing speed. The integration of graphene as an efficient spin transport channel in the chiral domain walls technology depends on the ability to fabricate graphene-based perpendicular magnetic anisotropy (PMA) systems with tailored interfacial SOC.

Studies on graphene-based magnetic systems are not abundant and, typically, make use of metallic single crystals as substrates which jeopardize the exploration of their transport properties (since the current is drained by the substrate). To solve this challenge, the IMDEA Nanociencia leading team succeeded to fabricate high-quality epitaxial asymmetric gr/Co/Pt(111) structures grown on (111)-oriented oxide substrates. The quality of the interfaces was checked by low-energy electron diffraction and also by advanced high-resolution transmission microscopy at the Universidad Complutense de Madrid (UCM) microscopy centre and resonant X-ray specular reflectivity at BOREAS beamline at ALBA (see fig.1). The magnetic anisotropy and properties were investigated by magneto-optical Kerr magnetometry in IMDEA and Universidad Autónoma de Madrid (UAM) and complemented with element resolved XMCD magnetometry also at BOREAS beamline. Finally, the chirality of the magnetic domain walls was analysed using a customized magneto-optical Kerr effect microscope and pulse field electronics in collaboration with the team at Institut Néel in Grenoble.

>Read more on the ALBA website

Advanced Light Source upgrade project moves forward

2018/09/252018/09/27

An upgrade of Berkeley Lab’s X-ray facility clears next stage in federal approval process.

The Advanced Light Source (ALS), a scientific user facility at the Department of Energy’s (DOE) Lawrence Berkeley National Laboratory (Berkeley Lab), has received federal approval to proceed with preliminary design, planning and R&D work for a major upgrade project that will boost the brightness of its X-ray beams at least a hundredfold.

The upgrade will give the ALS, which this year celebrates its 25th anniversary, brighter beams with a more ordered structure – like evenly spaced ripples in a pond – that will better reveal nanoscale details in complex chemical reactions and in new materials, expanding the envelope for scientific exploration.
“This upgrade will make it possible for Berkeley Lab to be the leader in soft X-ray research for another 25 years, and for the ALS to remain at the center of this Laboratory for that time,” said Berkeley Lab Director Mike Witherell.

Steve Kevan, ALS Director, added, “The upgrade will transform the ALS. It will expand our scientific frontiers, enabling studies of materials and phenomena that are at the edge of our understanding today. And it will renew the ALS’s innovative spirit, attracting the best researchers from around the world to our facility to conduct their experiments in collaboration with our scientists.”

Image: A computer rendering providing a top view of the ALS and shows equipment that will be installed during the ALS-U project.
Credit: Berkeley Lab

How did humans live 5000 years ago?

2018/09/242018/09/27

Researchers from the Cyprus Institute, in collaboration with the Iranian Center of Archaeological Research, have worked around the clock for a week on ID16A to discover more about the lifestyle of our ancestors.

How did people live 5000 years ago? What did they eat? What can we learn of their health? Were they exposed to contaminants? To answer these questions with various techniques researchers first need to understand more about the preservation state of ancient human hair. In order to do this, a team from Cyprus Institute is scanning hair remains found within burials at the ancient site of Shahr-I-Sokhta, in Iran.
In this urban settlement, at a crossroads of important ancient trade routes that later became part of the Silk Road, there was busy commercial and manufacturing activity around metal and precious materials as evidenced by the artifacts found onsite during archaeological excavations. Archaeologists have also found remains of the inhabitants of the city dating to the 3^rd millennium BC, and their state of preservation is remarkable. “The climate in this area is very arid and hot, and this has led to preservation of body tissues not often found with human skeletons, including hair”, explains Kirsi Lorentz, assistant professor at the Cyprus Institute.

Image: Aerial view of the Shahr-I-Sokhta site, in Iran.
Credit: Media Rahmani