Researchers at the National University of Singapore (NUS) have developed a concept to induce and quantify spin splitting in graphene, opening new possibilities for low-power electronics in the field of two-dimensional spintronics.
As the demand for low-power electronics continues to grow, researchers are exploring alternative solutions to address the issue of Joule heating, which poses a significant challenge in modern devices. One promising approach lies in the field of spintronics, where spin is used instead of charge in logic circuits. Graphene, a two-dimensional material with exceptional spin properties, has emerged as a potential candidate for spintronics applications. However, the lack of direct methods to determine spin-splitting energy and limitations in graphene’s spin properties have hindered progress. Now, a team of physicists from NUS has developed a groundbreaking concept to induce and directly measure spin splitting in graphene, paving the way for advancements in two-dimensional spintronics.
Overcoming Challenges in Graphene Spin Properties
Graphene, with its long spin diffusion length and spin lifetime, has long been considered an ideal material for spintronics. However, the challenge lies in inducing spin polarization in graphene and quantifying its spin-splitting energy. To address these challenges, the NUS research team led by Professor Ariando developed an innovative concept using the Landau fan shift. This shift refers to the change in intercept when plotting oscillation frequency with charge carriers, providing a direct measurement of spin-splitting energy. By stacking a monolayer of graphene on top of a magnetic insulating oxide, the researchers were able to induce and quantify a spin-splitting energy value of 132 meV in the magnetic graphene.
Tunability and Spin Polarization in Graphene
The tunability of spin-splitting energy in graphene is crucial for its practical applications in spintronics. The NUS team achieved this by employing a technique called field cooling, which allowed them to tune the degree of spin-splitting in graphene. Additionally, the researchers utilized X-ray magnetic circular dichroism (XMCD) to uncover the origins of spin polarization, providing further validation of their experimental findings. The high spin polarization observed in graphene, coupled with its tunability, offers a promising avenue for the development of low-power electronics in the field of two-dimensional spintronics.
Experimental Validation and Theoretical Consistency
To support their experimental findings, the NUS team collaborated with a theoretical team led by Professor Zhenhua Qiao from the University of Science and Technology of China. Using first principle calculations, the theoretical results obtained were consistent with the experimental data, further confirming the accuracy of their approach. The researchers also employed machine learning techniques to fit their experimental data based on a phenomenological model, providing deeper insights into the tunability of spin-splitting energy through field cooling.
Practical Applications and Future Directions
The ability to efficiently tune the spin polarization of current opens up possibilities for the development of all-electric spin field-effect transistors, which could revolutionize low-power consumption and ultrafast speed electronics. Building upon their proof-of-concept study, the NUS research team plans to explore the manipulation of spin current at room temperature. Their ultimate goal is to apply their findings in the development of 2D spin-logic circuitry and magnetic memory/sensory devices. With the rapid development and significant interest in the field of 2D magnets and stacking-induced magnetism in atomically thin van der Waals heterostructures, the researchers believe their results can be extended to various other 2D magnetic systems.
Conclusion:
The breakthrough achieved by NUS physicists in inducing and quantifying spin splitting in graphene opens up new possibilities for the field of two-dimensional spintronics. By directly measuring spin-splitting energy using the Landau fan shift, the researchers have overcome key challenges in graphene’s spin properties. The tunability and high spin polarization observed in graphene offer promising avenues for the development of low-power electronics. The research team’s future work aims to explore the manipulation of spin current at room temperature and apply their findings in the development of 2D spin-logic circuitry and magnetic memory/sensory devices. With the potential to revolutionize low-power consumption and ultrafast speed electronics, the field of two-dimensional spintronics holds exciting prospects for the future.
Leave a Reply