By G.P. Thomas
Ramesh Mani, an associate professor of physics at Georgia State University (GSU), and Walter de Heer, Regents' Professor of physics at the Georgia Institute of Technology (Georgia Tech), have developed a new technique to study the spin characteristics of electrons in graphene.
The study findings have been reported in Nature Communications. Electrons demonstrate two key properties, namely charge and spin. Most electronic devices are based on the electric charge. In this study, the researchers measured spin, which is the building block of new spintronics devices and holds potential for technologies such as quantum computing.
Graphene is believed to be an essential element for spintronic devices; however, extensive research is required to understand the material’s capability. This study by GSU and Georgia Tech is a significant progress towards this research.
Mani explained that he along with the team tried to detect spin resonance using the electrical resistance. When the device is illuminated by microwaves, the spin-splitting energy is equalized by the microwave energy. The device’s resistance is altered when the microwave energy is absorbed by the device. However, it is difficult to see this very small effect.
Fortunately, the use of graphene enabled the researchers to witness the effect. The electrical measurement of spin resonance is particularly helpful for nanoscale devices. This measurement allows the researchers to directly measure characteristics such as the spin splitting energy and the spin relaxation time.
This advancement in measuring the spin properties of the electrons in graphene paves the way to enhance the nanomaterial for spintronic applications. Mani informed that the experiments carried out at GSU were laborious, while the production of graphene performed at de Heer's laboratory was time consuming and required a vast experience. The researchers used advanced equipment for measurements, which involved the immersion of samples in liquid helium at near absolute zero temperature.