Talieh Ghiasi
Talieh Ghiasi is ‘the ninth of the Excellence Fund’. With the support of this fund, she was appointed from 1 September onwards as Assistant Professor at the Department of Quantum Nanoscience (QN) at the Faculty of Applied Sciences. Leading her own research team, she will be a pioneer at TU Delft to continue to shape the new research area of quantum spintronics.
Talieh Ghiasi is known as a successful pioneer and experimental quantum nano scientist. After a bachelor and master in solid-state physics at Iran University of Science and Technology, she received her doctorate cum laude in Groningen as part of the spintronics group of Professor Bart van Wees. The title of her doctoral dissertation was: ‘Proximity-induced spin-orbit and exchange coupling in graphene-based heterostructures’. After this, she completed a postdoc at TU Delft in the Quantum Nanoscience lab led by Professor Herre van der Zant, where she converted from traditional spintronics to quantum spintronics. Recently, she completed a second postdoc at Harvard University – supported by the prestigious Rubicon grant from the NWO (Dutch Research Council). In the meantime, Ghiasi received the Minerva prize 2023 from the Dutch Physics Council (DPC) and the Nederlandse Natuurkundige Vereniging (Netherlands’ Physical Society; NNV) for talented, experimental, female physicists. And she already has her name added to almost 20 publications. To these achievements, she added an NWO Veni grant this year.
Ghiasi’s research focuses on a new and rapidly developing research area within quantum technology: the field of spintronics. ‘We are going to use new (quantum) materials and different quantum phenomena for spintronics’, Ghiasi promises.
Spintronics versus regular electronics
Regular electronics uses electrons and their charge to process information. However, these electrons also have another characteristic: their spin. Their spin has two basic orientations: spin-up and spin-down. These two orientations can occur simultaneously – a quantum characteristic. Because of this, you can use not only the charge, but also the spin of electrons to process and store information. That is the core principle of spintronics. This technology has major potential – compared to conventional electronics – for sensor technology, information storage and data processing.
Faster, more stable, and more energy efficient circuits
Current spintronics research focuses specifically on refining materials, designing new devices and improving the integration with existing semiconductor technology. However, Ghiasi’s research takes it one step further. She orients herself on the application of spintronics combined with other phenomena from quantum mechanics. With this, she not only focuses on materials but also the quantum characteristics within those materials. As such, she hopes to develop next generation quantum spintronic circuits. Which have the potential to be faster, more reliable and more energy-efficient than traditional spintronic or electronic devices. And could, with time, even become fault tolerant. In other words: coupling spintronics to quantum mechanics can provide wholly new perspectives for information storage and processing.
Societal impact: green ICT?
With her research, Ghiasi aims to develop a new standard for operations using spintronics, which can facilitate fault tolerant calculation and memory technology: a promising route to energy efficient electronics, advanced memory systems and eventually quantum computers. ‘Our research is on interface between spintronics, quantum materials and quantum computing,’ Ghiasi concludes. ‘Conventional electronics has a number of limitations, such as heat production and energy loss. The next generation circuits based on quantum spintronics that we want to develop will be circuits that are faster, energy-efficient and run on low power. Because of this, they will have a lower impact on the environment than current technology. This could be a solid sustainable solution in the digital era. Moreover, we hope to bridge the gap between fundamental research and practical applications.’
‘Flying start thanks to Excellence Fund’
Ghiasi chose to continue her research at TU Delft because of Delft’s reputation as centre for quantum technology and quantum nanoscience. This fame is mostly due to the expansive quantum ecosystem, with departments such as Quantum Nanoscience and Quantum Technology, the expertise surrounding semiconductors, superconductors, quantum materials and quantum circuits, and the advanced facilities and modern cleanrooms, which are vital to nanofabrication. ‘This experimental research requires broad financial support for high tech machines such as ultra-low temperature measuring systems or to make Van der Waals-heterostructures based on two-dimensional materials,’ Ghiasi explains. ‘In addition, of course, to the ability to attract excellent researchers. Thanks to the contribution of the Excellence Fund – and therefore, thanks to the donors – I can truly give my laboratory for quantum spintronics a flying start.’
Breakthrough with quantum spin currents in graphene
Researchers of the Van der Zant lab, among which Talieh Ghiasi, have demonstrated quantum spin currents in graphene (the quantum spin Hall (QSH) effect) for the first time without external magnetic fields. The QSH effect allows electrons to move along the edges of the graphene without obstacles, while all their spins are oriented in the same direction (‘up’ or ‘down’). ‘Previously, large external magnetic fields were always necessary to detect quantum spin currents in graphene. These fields are not compatible with electronic circuits and are practically impossible to integrate on-chip,’ Talieh explains. ‘That we can now create quantum spin currents without external magnetic fields opens doors to future applications of these quantum spintronics devices.’ This research has been published in the prestigious ‘Nature Communications’.