Spintronic devices have revolutionized the field of electronics by utilizing the spin of electrons to enable high-speed processing and low-cost data storage. One key phenomenon that has fueled advancements in spintronic devices is spin-transfer torque. However, recent research has shown that spin-orbit torque (SOT) is emerging as a promising alternative to spin-transfer torque. The origin of SOT lies in a phenomenon called the spin Hall effect (SHE) in non-magnetic materials. In this article, we will explore the influence of Dirac band hot spots on the temperature dependence of SHE in tantalum silicide (TaSi2) and how this knowledge can be harnessed for the development of high-temperature, ultrafast, and low-power SOT spintronic devices.
Tantalum Silicide and Berry Phase Engineering
Tantalum silicide (TaSi2) has garnered significant interest due to its unique band structure, which contains Dirac points near the Fermi level. The presence of these Dirac points makes TaSi2 an ideal material for practicing Berry phase engineering. Berry phase monopoles, which are regions of special significance for the Berry phase, play a crucial role in achieving a large SHE. Therefore, materials with suitable Berry phase hot spots are essential for engineering the SHE. Associate Professor Pham Nam Hai and his team from the Department of Electrical and Electronic Engineering at Tokyo Institute of Technology recently conducted a study to investigate the influence of Dirac band hot spots on the temperature dependence of SHE in TaSi2.
The researchers performed a series of experiments to analyze the temperature dependence of spin-orbit torque (SOT) efficiency in TaSi2. Their findings, published in the journal Applied Physics Letters, revealed interesting behavior. From 62 K to 288 K, the SOT efficiency of TaSi2 remained relatively unchanged, similar to conventional heavy metals. However, beyond 288 K, there was a sudden increase in SOT efficiency, nearly doubling at 346 K. This unique temperature dependence was distinct from the behavior observed in conventional heavy metals and their alloys.
Upon closer examination, the research team attributed the sudden increase in the spin Hall effect (SHE) at high temperatures to the presence of Berry phase monopoles in TaSi2. These results sparked interest in Berry phase monopole engineering as a strategy to enhance SOT efficiency at high temperatures. Dr. Hai emphasizes the potential of this approach, stating, “These results provide a strategy to enhance the SOT efficiency at high temperatures via Berry phase monopole engineering.”
The study conducted by Dr. Hai and his team sheds light on the possibilities of using Berry phase monopole engineering to effectively utilize the spin Hall effect in non-magnetic materials. Furthermore, this research paves the way for the development of high-temperature, ultrafast, and low-power spin-orbit torque spintronic devices. The ability to harness the unique properties of TaSi2’s band structure opens up exciting opportunities for the future of spintronic device technology.
Spintronic devices have revolutionized the field of electronics, and the exploration of alternative phenomena like spin-orbit torque (SOT) is crucial for further advancements. The study conducted by Dr. Hai and his team highlights the influence of Dirac band hot spots on the temperature dependence of SHE in tantalum silicide (TaSi2). Their findings provide valuable insights into the potential of Berry phase monopole engineering for enhancing SOT efficiency at high temperatures. This research opens up new avenues in the development of high-temperature, ultrafast, and low-power spintronic devices. As the field of spintronics continues to evolve, the utilization of novel materials and engineering techniques, such as Berry phase monopole engineering, holds great promise for the future of electronic devices.