Tantalum silicide's key role in high-temperature spintronic devices

Tantalum silicide's key role in high-temperature spintronic devices
by Riko Seibo
Tokyo, Japan (SPX) Jan 10, 2024

In the realm of advanced electronic technology, spintronics has emerged as a promising field. This technology, which utilizes the electron spin in addition to its charge, aims for rapid data processing and cost-effective storage solutions. Central to the progress in spintronics is the concept of spin-orbit torque (SOT), a phenomenon now considered a viable alternative to the traditional spin-transfer torque mechanism.

Recent studies have focused on unraveling the origins of SOT, particularly in non-magnetic materials. A critical discovery in this context is the significance of the spin Hall effect (SHE). SHE's efficiency in these materials is largely dependent on their electronic structures, specifically the presence of a "Dirac band" structure. This arrangement of electrons is crucial for large SHE as it harbors "hot spots" for the Berry phase, a quantum factor intrinsic to SHE. Therefore, materials with optimal Berry phase hot spots are essential for engineering SHE effectively.

Tantalum silicide (TaSi2) has garnered interest due to its promising Dirac band structure, which positions it as an ideal candidate for Berry phase engineering. A team from the Tokyo Institute of Technology, led by Associate Professor Pham Nam Hai, delved into this aspect. Their study, published in Applied Physics Letters, explored the impact of Dirac band hot spots on SHE's temperature dependence in TaSi2. Dr. Hai elucidates the significance of their research, noting, "Berry phase monopole engineering is an interesting avenue of research as it can give rise to efficient high-temperature SOT spintronic devices such as the magneto-resistive random-access memory."

The team's experiments revealed that TaSi2 maintained consistent SOT efficiency from 62 K to 288 K, mirroring the behavior of conventional heavy metals. However, a notable change occurred when the temperature was raised further. At 346 K, the SOT efficiency nearly doubled, accompanied by a similar increase in SHE. This marked deviation from conventional heavy metals' behavior was attributed to Berry phase monopoles.

Dr. Hai emphasizes the implications of their findings, stating, "These results provide a strategy to enhance the SOT efficiency at high temperatures via Berry phase monopole engineering." This strategy paves the way for the development of high-temperature, ultrafast, and low-power SOT spintronic devices, offering a novel pathway in the field of spintronics.

The study conducted by Tokyo Tech's team stands as a significant contribution to the understanding of high-temperature SOT in spintronics. By harnessing the unique properties of materials like TaSi2 and employing Berry phase monopole engineering, researchers can push the boundaries of spintronic technology, offering new solutions for efficient, high-performance electronic devices.

Research Report:Enhanced spin Hall effect at high temperature in non-centrosymmetric silicide TaSi2 driven by Berry phase monopoles