EAPSI: Electrical generation of a spin current in nanowires

Goble Nicholas J, Cleveland OH

Investigators

Abstract

Electrical conduction is an interesting phenomenon whose study has led to countless physical discoveries. At first glance, the casual flow of electrons through a conductor seems to be a simple system, but the complexities of the system quickly unravel as it is studied in more detail. Heat, impurities, crystal structure, and quantum effects are a few simple examples of complexities that are regularly considered in charge carrying conductors. One such complexity is the consideration of electron spin, analogous to magnetic polarity. Theoretically, spin-dependent currents are perfectly possible to generate and measure. However, modern electronics are not dependent on electron spin, so electrical conductivity is independent from it. Using spin-dependent currents in conductors opens up the field of spintronics and will lead to numerous applications such as spin transistors, quantum computing, and larger information storage media. In collaboration with Dr. ZhiDong Zhang at Shenyang National Laboratory for Materials Science in China, this study plans to significantly impact the field of spintronics by electrically generating and controlling a spin polarized current. Topological materials offer robust protection to certain material properties, making them ideal candidates for studying spin polarized currents. Topologically invariant states may induce long quantum coherence times to allow for quantum computing at high temperatures and induce dissipationless transport useful for low power devices. In that sense, this research will use bismuth selenide (Bi2Se3) nanowires, a known topological material, to generate, measure, and control a topologically protected spin polarized current. The topological states that provide long quantum coherence times at room temperature are also known as surface states, as opposed to bulk states. Since nanowires have large surface to bulk ratios, they are ideal for maximizing the effect of the topologically invariant states. The generation and study of a robust spin polarized current is a necessary step towards the next age of information processing. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.