Materials Australia Magazine | September 2021 | Volume 54 | No.3

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BREAKING NEWS 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.

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.

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.

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“The hub will solve industry challenges and translate research and development into commercial opportunities and outcomes,” Professor Khalili said. WWW.MATERIALSAUSTRALIA.COM.AU