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Electrons On The Edge: Atomically-Thin Quantum Spin Hall Materials

Quantum spin Hall insulators are a class of 2D topological states of matter that are electrically insulating in their interior. But a research team from ANSTO has recently analysed materials engineering alongside their theoretical description to understand classical and quantum electronic device applications. Unlike semiconductors, they carry a pair of one-dimensional (1D) metallic states, which are strictly confined to their edges. Particular to these ‘edgy’ 1D electrons are helical structures, where the spins of conduction electrons are aligned and tied to the direction that electrons move along the 1D edge. These helical properties offer potential solutions for problems in electronics and spintronics, as well as quantum electronic devices. This exotic and topological state of matter was first realised in carefully designed, and layered semiconductor heterostructures. These classes of atomically-thin crystals are emerging, similar to the famous graphene, which hosts this electronic state of matter as an intrinsic property. For example, the temperature range in which the exotic edge states can be harnessed scales with the properties of these crystals, such as the coupling strength of the electron’s spin to its orbital momentum. Quantum spin Hall insulators may be used for new kinds of electronics that consume less power, but this would require room-temperature operations to avoid costly cooling. This study was led by Associate Professor Weber, who specialises in the design, fabrication and measurement of molecular to atomic-scale electronic devices. The study was supported by the National Research Foundation Singapore and the Singapore Ministry of Education.

Nanyang Assistant Professor Bent Weber (left) and Dr Michael S. Lodge in the Quantum Spin Hall lab. Photo credit: SPMS Communications, College of Science, NTU Singapore. Prof Weber’s laboratory is equipped with a growth facility for quantum spin Hall materials, combined with a sensitive scanning tunnelling microscope (shown), operating at extremely low temperature. Photo credit: SPMS Communications, College of Science, NTU Singapore

UNSW Tops ARC Research Hub Grants

More than $9 million in ARC grants was recently awarded to two UNSW projects—topping the nation for the largest share of funding. The two projects will provide research into sensors for the health sector and new technologies for Australia’s infrastructure needs. Together, they will ensure innovative research and stronger connections with the health, urban, energy and resources sectors. Professor Nicholas Fisk, who is UNSW’s Deputy ViceChancellor (Research and Enterprise), said the two projects will transform UNSW’s research capabilities. “To secure a quarter of the national awards to transform research for the new industrial economies is outstanding.” “These two hubs are exemplars of scale and collaboration, involving a total of nine universities, nearly 50 partner organisations, over 60 chief investigators with two-thirds at UNSW, and a total cash and in kind spend of around $25 million,” he explained. Professor Chun Wang will lead the hub to position Australia at the forefront of connected health by integrating sensor science with data analytics, regulatory approval and certified manufacturing capabilities. “The health sensors will be able to monitor biophysical and biochemical markers to aid rehabilitation and chronic disease management, and support frail, ageing and at-risk populations,” Professor Wang said. Meanwhile, Professor Nasser Khalili will lead a hub awarded $4.98 million. The hub will deliver technologies to address Australia’s infrastructure needs in the urban, energy and resources sectors. “The hub will solve industry challenges and translate research and development into commercial opportunities and outcomes,” Professor Khalili said.

It's All About The Interface With Multi-Use Polymer Brushes

The University of Newcastle and UNSW Sydney are using advanced neutron scattering techniques at ANSTO to carry out research on the structure of polymers in complex salt environments. This research will provide a way to predict the behaviour of polymers for real-world applications. Researchers have analysed polymer brushes—densely packed arrays of polymer chains that are tethered to flat surfaces—for use in environmentally-friendly cleaning products and other applications. The behaviour of many of these applications is determined by the interface between the polymer, the surface substrate and the nanostructure of the brush. Professors Grant Webber and Erica Wanless at the University of Newcastle, Associate Professor Stuart Prescott at UNSW, and Dr Andrew Nelson from ANSTO, examined and fully characterised the convoluted behaviour and properties of polymer brushes in complex environments. Past and present investigations have relied on neutron reflectometry, because of its unique ability to characterise the interface at a nanoscale. “Experiments using the neutron reflectometer Platypus and Spatz provided in situ information about structural changes to the polymer molecules in real time,” said Dr Nelson. “The development of dedicated sample environments for the polymer brushes by Associate Professor Prescott and data analysis software by his recent PhD graduate Isaac Gresham, means we are really well set up for these experiments,” he explained. The team is also working with industry partners to use this knowledge to develop environmentally-friendly cleaning agents for household and personal care products, and more water-efficient mineral processing additives for the mining sector.

Inducing And Tuning Spin Interactions In Layered Material By Inserting Iron Atoms, Protons

Researchers have discovered that magnetic-spin interactions, which allow spin-manipulation by electrical control, can have potential applications in energy-efficient spintronic devices. An antisymmetric exchange known as Dzyaloshinskii-Moriya interactions (DMI) is vital to form various chiral spin textures, such as skyrmions, and permits their potential application in energy-efficient spintronic devices. But a recent China-Australia collaboration has illustrated that DMI can be induced in a layered material tantalum-sulfide (TaS2) by intercalating iron atoms, and can be further tuned by gate-induced proton intercalation. Generally, chiral spin textures are stabilised by DMI. As such, introducing and controlling DMI in materials is the key to searching and manipulating the chiral spin textures. “Tantalum-sulfide is one of the large family of transition metal dichalcogenide investigated by FLEET for low-energy applications,” said Dr Guolin Zheng from RMIT University. The team successfully realised a sizable DMI in the TaS2 by intercalating Fe atoms. But the researchers found that electrically controlling the DMI can be a challenging process. “Both conventional electric-field gating, and the widelyused alternative technique of ion-liquid (Li+) gating have hit stumbling blocks in the electrical control of DMI in itinerant ferromagnets, because the electric-field and Li+ can only modulate the carriers close to the surface,” Dr Zheng explained. The RMIT research team developed a new protonic gate technique, and successfully illustrated that DMI can be dramatically controlled by gate-induced proton intercalations. In addition, the team was able to significantly change the carrier density and further tune the DMI through the Ruderman-Kittel-Kasuya-Yosida mechanism. This refers to the coupling of nuclear magnetic moments.

Hall-bar device on solid proton conductor, used to measure Hall resistivity under different conditions. Crystal structure, showing iron atoms (red) in tantalum-sulfide structure.

Australian-First Tech: Next Step In Waste Transformation Innovation

Left to right: Maree Lang (Managing Director, Greater Western Water), Steve McGhie (Member for Melton), Lara Olsen (Managing Director, South East Water), Dean Barnett (Program Director, Intelligent Water Networks), Associate Professor Kalpit Shah (RMIT). Photo: Shawn Smits Photography. Photo courtesy of RMIT University.

The next iteration of waste transformation innovation is underway through research developed at RMIT University. The breakthrough research involves the water industry transforming biosolids headed for landfill into reusable products for farmers. The technology is the first of its kind in Australia, and uses high temperatures to destroy pathogens and micro plastics in biosolids, creating high-value biochar. It allows farmers and the wider agricultural industry to reuse 100 per cent of the product safely. “This collaboration will enable the water industry to find alternative markets for biosolids, reducing waste going to landfill and allowing 100 per cent of products to be reused or recycled,” said Steve McGhie, who is the Member for Melton. Mr McGhie recently inspected the technology, while it was on trial at the Melton Recycled Water Plant in Victoria. The technology will make biosolids management more environmentally sustainable and cost effective, and help to reduce carbon emissions for both the water and agriculture industries. Farmers and the wider agriculture industry commonly use biosolids as fertiliser and soil amendment. Around 30 per cent of the world’s biosolids resource is stockpiled or sent to landfill, which creates an environmental challenge. “By creating a safe product with a steady supply stream, we’re also providing our farmers and the wider agriculture industry a product which is completely natural and can improve soil health and fertility,” Mr McGhie said. The next stage of the trial will scale up the technology and have a unit in place at a water recycling plant over a longer period of time. The technology was supported through funding from RMIT’s Enabling Capability Platforms.

Transforming The Layered Ferromagnet Fe5gete2 For Future Spintronics

A RMIT University-led international collaboration has achieved record-high electron doping in a layered ferromagnet, which causes a magnetic phase transition with significant promises for future electronics The study demonstrates that ultra-high electron doping concentration can be induced in the layered van der Waals (vdW) metallic material Fe5GeTe2 by proton intercalation. In addition, researchers found that it can cause a transition of the magnetic ground state from ferromagnetism to antiferromagnetism (AFM). Compared to itinerant ferromagnets, AFMs have unique advantages as the building blocks future spintronic devices. Their robustness to stray magnetic fields makes them suitable for memory devices. “We chose to work with newly synthesised vdW itinerant ferromagnet Fe5GeTe2,” said FLEET Research Fellow Dr Cheng Tan from RMIT. “Our previous experience on Fe3GeTe2 enabled us to quickly identify and evaluate the material’s magnetic properties, and some studies indicate Fe5GeTe2 is sensitive to local atomic arrangements and interlayer stacking configurations, meaning it would be possible to induce a phase transition in it by doping,” Dr Cheng explained. The team investigated the magnetic properties in Fe5GeTe2 nanosheets of various thicknesses by electron transport measurements. Initial transport results showed the electron density in Fe5GeTe2 is high as expected. This indicates that the magnetism is hard to be modulated by traditional gate-voltage. Co-author Guolin Zheng explained it was worth the time, despite the high charge density in Fe5GeTe2. “We knew it was worth trying to tune the material via protonic gating, as we have previously achieved in Fe5GeTe2, because protons can easily penetrate into the interlayer and induce large charge doping, without damaging the lattice structure.” said Zheng.

Crystal structure and initial characterisation of F5GT.

A SP-FET transistor, with F5GT flake on a solid proton conductor (SPC) – scale = 10µm.

Team leader FLEET Chief Investigator Associate Professor Lan Wang in Class 100 clean room, RMIT.

New Technique Breaks The Mould For 3D

Printing Medical Implants.

A tiny and intricate biomedical structure created with the new technique. Image courtesy of RMIT University.

Researchers have flipped traditional 3D printing techniques to create some of the most intricate biomedical structures. RMIT researchers Stephanie Doyle and Dr Cathal O’Connell. Image courtesy of RMIT University. The breakthrough advances the development of new technologies for regrowing bones and tissue. The emerging field of tissue engineering aims to harness the human body’s natural ability to heal itself, to rebuild bone and muscle lost to tumours or injuries. Biomedical engineers have designed and developed 3D printed scaffolds that can be implanted in the body to support cell regrowth. An RMIT University-led research team, collaborated with clinicians at St Vincent’s Hospital in Melbourne to overturn the conventional 3D printing approach. Instead of making the bioscaffolds directly, the team 3D printed moulds with intricately-patterned cavities then filled them with biocompatible materials, before dissolving the moulds. Using the indirect approach, the team created fingernailsized bioscaffolds full of elaborate structures that were considered impossible with standard 3D printers. “The shapes you can make with a standard 3D printer are constrained by the size of the printing nozzle—the opening needs to be big enough to let material through and ultimately that influences how small you can print,” said lead researcher Dr Cathal O’Connell. “By flipping our thinking, we essentially draw the structure we want in the empty space inside our 3D printed mould. This allows us to create the tiny, complex microstructures where cells will flourish,” Dr O’Connell explained. Other approaches are able to create impressive structures, but only with precisely tailored materials, tuned with particular additives or modified with special chemistry. “Importantly, our technique is versatile enough to use medical grade materials off-the-shelf,” Dr O’Connell said.

'Miracle Protein' Biosensor Set To Transform Early Cancer Detection

A commercialisation agreement for a high-tech biosensor is paving the way to improved diagnosis, monitoring and treatment for cancer patients around the globe. Science from Deakin University has discovered a world-first, point-of-care cancer sensor, which could be on the market within five years. Dr Wren Greene and his colleagues at Deakin have unlocked the potential of lubricin, a non-sticking ‘miracle protein’ found in human joints, to reliably detect cancer. The protein has an outstanding potential for earlier treatment, better monitoring and improved long-term outcomes for cancer patients. Universal Biosensors, an industry partner of Deakin, formalised an exclusive licence and supply agreement with US company Lubris BioPharma LLC to develop the technology for market. Universal Biosensors expects to invest up to $10 million to achieve commercialisation over the next five years. "To be able to identify and measure, then monitor the rate of a healthy human cell becoming a cancer cell from a handheld, point-of-care biosensor device is an exciting prospect for UBI," said John Sharman, who is the Chief Executive Officer at Universal Biosensors. "Putting aside the possibility for early screening and then staging of cancer from a handheld device, the blood testing market for the monitoring of cancer remission patients annually is estimated at $17 billion.” “It would be wonderful if the initiative could improve the lives of many of the 131 million cancer remission patients around the world," Mr Sharman said. The Deakin research team is also exploring other potential lubricin sensor applications, including the testing of water quality, fire retardant detection and use in the food and beverage industry.

CSIRO Appoints New Chief Scientist

CSIRO has appointed Professor Bronwyn Fox as Chief Scientist, close to 30 years after she began her career as a research assistant at the organisation. Professor Fox is CSIRO’s fourth female Chief Scientist, and joins the agency from Swinburne University of Technology. “It is wonderful to return to CSIRO as Chief Scientist after starting as a 22-year-old research assistant, and to be able to champion science research and capability, working with industry and fostering STEM careers,” Professor Fox said. Professor Fox was the founding Director of Swinburne’s Manufacturing Futures Research Institute, with a mission to support the transition of Australia’s manufacturing sector to Industry 4.0. She also has a background as a materials and engineering scientist. “The depth of scientific research at CSIRO and its committed people are a unique and special national treasure and I look forward to taking up the role,” she said. CSIRO Chief Executive Dr Larry Marshall said Professor Fox brings great depth of scientific experience to the role. “Bronwyn exemplifies the CSIRO way—driven to deliver, brilliant but humble, leading by listening, and a generous collaborator.” “She has a long history of bringing together researchers from across multiple scientific domains and institutions, leveraging digital science, and helping industry to translate brilliant ideas into real world solutions,” Dr Marshall concluded. In addition to this role, Professor Fox is the Chair of the Australian Academy of Technology and Engineering (Victorian Division); a Fellow of the Academy of Technological Sciences and Engineering; and a Graduate of the Australian Institute of Company Directors.

Professor Bronwyn Fox will be CSIRO's next Chief Scientist. Image courtesy of the CSIRO. The nano-enhanced antibiotic effectively erradicates bacteria from lung cells (bottom line). Image courtesy of the University of South Australia.

Novel Nanotech Improves Cystic Fibrosis Antibiotic By 100,000-Fold

World-first nanotechnology developed by the University of South Australia could change the lives of thousands of people living with cystic fibrosis. Groundbreaking research can improve the effectiveness of the cystic fibrosis antibiotic Tobramycin, by increasing its efficacy by up to 100,000-fold. The new technology uses a biomimetic nanostructured material to augment Tobramycin, which is the antibiotic prescribed to treat chronic Pseudomonas aeruginosa lung infections in severe cases of cystic fibrosis. Cystic fibrosis affects one in 2,500 babies and causes severe impairments to a person’s lungs, airways and digestive system, traps bacteria and leads to recurrent infections. The research team believes the discovery could transform the lives of people living with cystic fibrosis. “Cystic fibrosis is a progressive, genetic disease that causes persistent, chronic lung infections and limits a person’s ability to breathe,” said PhD candidate, Chelsea Thorn, who worked on the research. “The disease causes thick, sticky mucus to clog a person’s airways, attracting germs and bacteria, such as Pseudomonas aeruginosa, which leads to recurring infections and blockages.” “Tobramycin is commonly used to treat these infections but increasingly antibiotics are failing to make any significant difference to lung infections, leaving sufferers requiring life-long antibiotic therapy administered every month,” she explained. Researchers enhanced the Tobramycin with a biometric, nanostructured, lipid liquid crystal nanoparticle-based material. Then, they tested it on a new lung infection model to showcase its unique ability to penetrate the dense surface of the bacteria and kill the infection. The technology is currently entering pre-clinical trials and hopes to be on the market in the next five years.

CMRP To Play Key Role In Space Technology Testing Network

L to R: Associate Professor Marco Petasecca, CMRP Director Distinguished Professor Anatoly Rozenfeld, and Professor Michael Lerch, head of the School of Physics. Image courtesy of the University of Wollongong. The University of Wollongong will contribute to a national network of facilities to test technology for use in space. The facilities, which are currently unavailable in Australia, will ensure electronics used in space can withstand the harsh conditions, undergo a qualification process, and a rigorous series of tests. The National Space Qualification Network (NSQN) will ensure local space industry organisations—and those across the Indo-Pacific region—undergo testing in Australia. The NSQN recently received $2.5 million in Federal Government funding. The NSQN features a six-partner consortium led by the Australian National University, Steritech, Nova Systems and Saber Astronautics. Associate Professor Marco Petasecca will lead the construction and operational aspects of the NSQN facility. “The environment in space is so harsh. The gradient of temperature, for example, is extreme: it's minus 270 degrees one moment and then suddenly, in close proximity to Earth, it may reach 250 degrees if exposed to sunlight,” he explained. But the NSQN will provide a point of difference, and motivate a new generation of space-enthusiasts. “Our NSQN industry partners will also play a critical role in building the stakeholder base that will need to utilise the University of Wollongong Node Facility.” “[It will] also [be] engaging in physics student training through work integrated learning, and student placements for those with an interest in current and emerging Australian space supply chain industries that will service this global market.” said Associate Professor Petasecca. The University of Wollongong’s contribution will be led by scientists from the Centre for Medical Radiation Physics.

Australian Researchers Create Quantum Microscope That Can See The Impossible

In a major scientific leap, researchers from the University of Queensland have created a quantum microscope that can reveal biological structures that would otherwise be impossible to see. This paves the way for applications in biotechnology, and could extend far beyond into areas ranging from navigation to medical imaging. Professor Warwick Bowen, from the University’s Quantum Optics Lab and the ARC Centre of Excellence for Engineered Quantum Systems explained that the microscope is powered by the science of quantum entanglement. “This breakthrough will spark all sorts of new technologies— from better navigation systems to better MRI machines, you name it,” Professor Bowen said. “We’ve finally demonstrated that sensors that use it can supersede existing, non-quantum technology.” “This is exciting—it’s the first proof of the paradigm-changing potential of entanglement for sensing,” he explained. Australia has a quantum technologies roadmap, where quantum sensors are spurring a new wave of technological innovation in healthcare, engineering, transport and resources. “The best light microscopes use bright lasers that are billions of times brighter than the sun,” Professor Bowen said. The benefits are far-reaching, including a better understanding of living systems, to improved diagnostic technologies. Professor Bowen said there were potentially boundless opportunities for quantum entanglement in technology. “Entanglement is set to revolutionise computing, communication and sensing.” “Absolutely secure communication was demonstrated some decades ago as the first demonstration of absolute quantum advantage over conventional technologies,” he concluded. This development opens the door for further wide-ranging technological revolutions.

UQ team researchers (counterclockwise from bottom-left) Catxere Casacio, Warwick Bowen, Lars Madsen and Waleed Muhammad aligning the quantum microscope. Image courtesy of the University of Queensland.

Artist's impression of UQ's new quantum microscope in action. Image courtesy of the University of Queensland.