Spintronic devices have revolutionized the field of electronics by harnessing the intrinsic angular momentum of electrons, known as spin, for high-speed processing and low-cost data storage. While spin-transfer torque has been a key phenomenon in spintronic devices, recent research has focused on spin-orbit torque (SOT) as a promising alternative. Understanding the origin of SOT is crucial in developing efficient and advanced spintronic devices. A recent study conducted by researchers at the Tokyo Institute of Technology sheds light on the influence of Dirac band hot spots on the temperature dependence of SOT in tantalum silicide (TaSi2), opening up new possibilities for high-temperature, ultrafast, and low-power spintronic devices.
The researchers, led by Associate Professor Pham Nam Hai from the Department of Electrical and Electronic Engineering at Tokyo Tech, delved into the properties of TaSi2 and its band structure. TaSi2 has several Dirac points near the Fermi level in its band structure, making it an ideal candidate for Berry phase engineering. The presence of suitable Berry phase hot spots in materials is crucial for engineering the spin Hall effect (SHE), which plays a significant role in achieving efficient SOT. By utilizing Berry phase monopole engineering, the researchers aimed to enhance the SOT efficiency and explore the potential of TaSi2 for high-temperature spintronic devices.
The team conducted a series of experiments to investigate the temperature dependence of SOT in TaSi2. The results revealed that the SOT efficiency remained almost unchanged from 62 K to 288 K, similar to conventional heavy metals. However, a surprising turn of events occurred when the temperature was further increased. The SOT efficiency suddenly doubled at 346 K, accompanied by a corresponding increase in the SHE. This behavior deviated significantly from the typical behavior observed in conventional heavy metals and their alloys.
Upon careful analysis, the researchers identified Berry phase monopoles as the driving force behind the sudden increase in SHE at high temperatures. The presence of these monopoles enabled efficient Berry phase monopole engineering, paving the way for enhanced SOT efficiency in non-magnetic materials like TaSi2. The findings of this study highlight the potential of Berry phase monopole engineering in utilizing the SHE effectively and provide a new pathway for the development of high-temperature, ultrafast, and low-power SOT spintronic devices.
The discovery of Berry phase monopole engineering as a strategy to enhance SOT efficiency at high temperatures holds tremendous implications for the future of spintronic devices. By exploiting the unique properties of materials like TaSi2, researchers can design and develop spintronic devices that are not only high-temperature resistant but also ultrafast and low-power. One potential application highlighted by Dr. Hai is the magneto-resistive random-access memory, which can benefit significantly from efficient high-temperature SOT spintronic devices.
The study conducted by the researchers at Tokyo Institute of Technology sheds light on the influence of Dirac band hot spots on the temperature dependence of SOT in TaSi2. Through the utilization of Berry phase monopole engineering, the researchers demonstrated the potential for enhancing SOT efficiency at high temperatures. This breakthrough opens up new avenues for the development of high-temperature, ultrafast, and low-power spintronic devices, bringing us closer to a future where spintronic technology revolutionizes the world of electronics.
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