Spin information of an electron, known as a pure spin current, is a key element in the development of spintronic devices for data storage, communication, and computing. Researchers from North Carolina State University and the University of Pittsburgh recently conducted a study to investigate how this spin information moves through chiral materials. The study revealed that the direction in which spins are injected into these chiral materials plays a crucial role in their ability to pass through, suggesting the potential use of chiral “gateways” in designing energy-efficient spintronic devices.
Spintronic devices differ from traditional electronic devices by utilizing the spin of an electron rather than its charge to generate current and transmit information. This unique approach aims to reduce energy consumption during data processing, as moving charge requires more energy and often leads to overheating issues in electronic devices like smartphones and computers. David Waldeck, a chemistry professor at the University of Pittsburgh, emphasizes the significance of moving spin information through materials without the need to move charge, highlighting the potential for more energy-efficient technologies in the future.
Chiral materials, which exhibit chirality or handedness, offer researchers a way to control the direction of spin within the material. Just like a left-handed glove cannot fit on a right hand, chiral materials have unique properties that make them ideal for manipulating spin information. Dali Sun, an associate professor of physics at North Carolina State University, explains that the sense of chirality in a material was previously believed to be crucial for spin movement. However, the research findings indicate that the angle between spin polarization and the chiral axis significantly influences the absorption of spin current in chiral materials.
The research team utilized two different methods, microwave particle excitation and ultrafast laser heating, to inject pure spin into selected chiral materials during the study. Both approaches resulted in the same conclusion regarding the relationship between spin polarization and chiral axis in spintronic materials. Jun Liu, an associate professor of mechanical and aerospace engineering at NC State, highlights the use of chiral cobalt oxide thin films with varying chirality to demonstrate the impact of spin alignment on material absorption. These findings challenge previous assumptions about spin behavior in chiral materials and open up new possibilities for designing spin-controlled electronic devices.
The study published in Science Advances sheds light on the potential of chiral gateways in electronic devices, where spin can only pass through in a specific direction. By aligning spin either parallel or anti-parallel to the material’s chiral axis, researchers observed a significant improvement in spin absorption, up to 3000%. This discovery paves the way for the development of novel chiral gateways that could enhance the performance and energy efficiency of spintronic devices. The researchers involved in the study, including postdoctoral researcher Rui Sun and graduate student Ziqi Wang from NC State, and Research Assistant Professor Brian Bloom from the University of Pittsburgh, are hopeful that further exploration of chiral materials and spin behavior will lead to groundbreaking advancements in the field of spintronics.