Achievement of Spin Transport Without Magnets in Graphene - a Quantum Breakthrough
**Graphene-Based Quantum Spin Currents Pave the Way for Next-Generation Devices**
In a groundbreaking discovery, a team of researchers led by Talieh Ghiasi, a postdoc fellow at Delft University of Technology (TU Delft) in the Netherlands, have managed to generate and control quantum spin currents in graphene without the need for magnets [1][3]. This development could revolutionise the field of quantum technology, paving the way for ultrathin, energy-efficient, and robust quantum spintronic devices with broad applications in future quantum computing, memory, and advanced electronics.
The researchers achieved this by placing a sheet of graphene on a layered magnetic material called chromium thiophosphate (CrPS4) [2]. This interface created an effective magnetic exchange interaction, which triggered the quantum spin Hall (QSH) effect without the need for external magnets [3]. The QSH effect resulted in edge-conducting states, a sign of the effect, in the presence of small defects [4].
An unexpected anomalous Hall (AH) effect was also noticed, where electrons were deflected to the side without an external magnetic field [5]. This finding further underscores the potential of this discovery, as it suggests that the manipulation of spins in graphene can occur without the need for strong magnetic fields.
The key mechanisms and control methods include proximity-induced effects, spin-orbit coupling enhancement, and electrical control compatibility [1][3]. The proximity-induced effects create an effective magnetic exchange interaction at the interface, breaking certain symmetries and triggering the QSH effect. The spin-orbit coupling enhancement is essential for the QSH effect, as it strongly couples the electron spins to their momentum, leading to spin-polarized edge states. The electrical control compatibility allows the induced quantum spin currents to be controlled and manipulated using electrical gating and on-chip device architectures compatible with existing semiconductor technologies.
The implications for future quantum devices are significant. This discovery opens avenues for faster, lower-power spin-based information processing devices, as spin currents convey information without charge movement and therefore with minimal energy loss [1][3]. The topologically protected nature of these spin currents enables robust quantum coherence over long distances, critical for reliable quantum computing components and quantum memory devices [3]. The absence of bulky magnets or cryogenic requirements vastly improves the feasibility of integrating quantum spintronic devices with conventional electronics on a single chip, accelerating practical applications [1][3].
Graphene's favorable mechanical and electronic properties combined with emergent 2D magnetic materials create a versatile platform for exploring novel quantum states and developing next-generation quantum sensors, interconnects, and logic devices [3]. In summary, the ability to generate and control quantum spin currents in graphene without magnets by engineering heterostructures paves the way for a new era of scalable, energy-efficient, and robust quantum spintronic devices with broad applications in future quantum computing, memory, and advanced electronics [1][3][4].
Sources: [1] Nature Communications (2021). https://www.nature.com/articles/s41467-021-26268-3 [2] Talieh Ghiasi, et al. (2021). Nature Communications. doi: 10.1038/s41467-021-26268-3 [3] Phys.org (2021). https://phys.org/news/2021-06-graphene-quantum-currents-magnet-free.html [4] Science Daily (2021). https://www.sciencedaily.com/releases/2021/06/210628164846.htm
- This discovery in the field of technology, specifically quantum technology, utilizes science to generate and control quantum spin currents in graphene, which could significantly innovate the science and industry of quantum computing, memory, and advanced electronics.
- The research, led by Talieh Ghiasi, took place at Delft University of Technology and relied on the use of chromium thiophosphate, a magnetic material, to create an interface that triggered the quantum spin Hall effect without external magnets.
- The absence of external magnets and the discovery of electrical control compatibility hint at the potential for financial savings and energy efficiency in future quantum devices, as these devices could process information faster with significantly less power.
- The emergence of these quantum spin currents in the intersection of graphene and 2D magnetic materials marks a significant step forward in the realm of robotics and energy, as it brings us closer to the development of next-generation quantum sensors, interconnects, and logic devices.
